Dear reader,                                                  May 2005

 

there are a couple of things I would like to tell you before you tackle this translation. 

 

Firstly, I am a “shark ager” and what I thought was a reasonable knowledge about sharks in all aspects turned out to be a rather sorry one.  I realised that I am definitely not a taxonomist, a “histologist” and an anatomist.  I bow with respect to the good old fashioned all-round scientist! I especially battled with the teeth structure and the intestine part, digging out school memories which I thought hadn’t exist anymore.  Some of his descriptions I didn’t understand myself which I am sure will be reflected in the translation.  Most of the nitty-gritty terms, again especially in the teeth and intestine section, one can’t find in a dictionary and one would only know, I suppose, with the right “insider knowledge”.  I even asked a dentist, trying to get an English translation for the things I tried to describe to him, without much success, unfortunately.  So I have to apologise for some of the sections.  I do hope that with the help of the Figures you will be able to work out what I (the author) am (is) talking about. 

 

Secondly, I decided to translate all the text literally, so the English will be not up to scratch.  On very few occasions I tired to translate the meaning of the sentence in a more modern English.  On few occasions text was not translated, which is mentioned.  Some comments (doubts, questions, non-understanding of the German text, interpretations) are given using footnotes.  Please note that the original text also has footnotes. Words in italic in brackets are not in the original text.  They are (mostly) added for better readability or to give alternatives, e.g. tube (duct/tunnel) - take your pick.  Please note that the original text also uses brackets.  Literal translation means that I am at a loss as how to translate correctly.

 

 

Contribution to the natural history of East-Asia.

 

Published (edited) by Dr. F Doflein.

 

On two enormous embryos from Lamna.

 

From Johannes Lohberger

 

From the Zoological Institute of the University of Leipzig.

 

With 5 plates.

 

In his travel description: “East-Asia travel, experiences and observations of a nature scientist in China, Japan and Ceylon (1906) Doflein reports:

 “ One of the most surprising discoveries for me was the egg of a giant shark[1].  I received it several times from fishermen, without ever getting the mother-animal which belongs to it.  Those eggs were taken out from the mother-animal, which obviously belongs to the live bearing sharks; with their enormous yolk mass they constitute the, to date, biggest known eggs from live bearing animals .  They are considerably bigger than ostrich eggs and also distinguished from all known shark eggs by (the fact that) the embryo is not connected with the yolk sack by a long, cord-like umbilical cord but is growing up directly on (top of it) it. ”

 

Those two shark eggs, amongst it the, to date, biggest known vertebrate egg, fell into the hands of my highly admired teacher, the Prof. Dr. Chum.  He was kindly enough to leave the two specimens to me with the determination[2], to closer investigate their anatomy and to determine in detail which species they belong to.  For this kindness and the advice and help.  .  .  .  .  .  (two sentences of heart gripping acknowledgements which I didn’t translate). 

 

In the beginning it would like to be remarked, that the two embryos are completely identical despite their difference in size, so that for the preparation to examine the internal anatomy I could restrict myself to the smaller specimen.  For the examination of the external features, mainly the head, the bigger animal was more suitable, as one finds the natural features, despite the preservation, good and better conserved as in the smaller one. 

 

The later examination will show that they belong to the genus Lamna.  Thus, they will be named as such in the prior sections. 

 

Also, in connection with the yolk sack, a remark must be pre-mentioned.  As one will find out, one does not deal with yolk sacks in the usual meaning.  If therefore Doflein regards it as the yolk sack which normally occurs with embryos and says that the embryo sits directly on it, in contradiction with all other known shark eggs, so it looks like he was deceived.  This deception, however, is easy to explain with the merely external (superficial) examination (observation) of the embryo.  Thus, to eliminate all errors a priori, it seems advisable, to use a different expression.  The expression “yolk stomach” will be proposed.  Why this particular term was chosen, will be seen in one of the later sections. 

 

 

II.  External features

(Fig. 1-3.)

 

After the decanting of the preserving alcohol, the bigger of the two specimens, also a unique specimen amongst the vertebrate eggs in aspect of size, has a mass of 2. 680 kg.  Even if one subtracts a part of the penetrated alcohol, one can still determine from the rest of the mass of our embryo that it is enormous and also creditable, when Braus (1906) writes the following:

 “ Doflein (1906, a. a. O. [3] , S. 267/68) described the, to date, biggest known vertebrate egg, also of a shark, but from an unknown species in Japan.  The yolk of the big, nearly fully developed embryos (a Carcharhid species[4]) measures along the longitudinal axis 22 cm.  The measurement along the lateral (transverse) axis, however, is considerably shorter.  Mr colleague Doflein was extremely kind to show me the original specimens this autumn.  The width is 13-14 cm.  The strong flattening is possibly caused by the preservation.  Nevertheless, the size off this yellow-egg (literal translation) can stand closely behind those which were produced by Dinornis and Aepyornis, as far as we can estimate this from the well preserved shells of those eggs (found in) the in the sand of New Zealand. 

 

As Braus previously mentioned, the longitudinal axis of the nice egg-shaped yolk stomach is nearly 22 cm.  The considerably smaller lateral axis has a length of 12.3 cm.  This strong flattening which can be observed especially in the bigger specimen, is surely , as Braus also mentions, due to the preservation.  The - also considerably big - embryo sits with nearly one third (of its size) on the yolk stomach.  It measures from the tip of the snout to the tip of the tail 55.3 cm.  The - nearly continuously - cylindrical body has a width of 6.3 cm in the position where it sits on the yolk stomach. 

 

The measurements are naturally smaller in the smaller object.  The total mass of the egg is 1.070 kg.  The longitudinal axis of the also egg-shaped yolk stomach is 14.9 cm and the lateral axis 9.5 cm.  In this case it seems that the preservation did not cause a heavy flattening.  The length of the embryo is 42.8 cm.  The width in the above mentioned position is 5.9 cm. 

 

A summary of all measurements, including those not yet mentioned, will be given at the end of this section. 

 

After (behind) the head, the body of our Lamni (plural for the two Lamna specimens, literal translation) naturally becomes wider and towards the tail narrower.  The head has the shape of a short, blunt cone with the upper part dyed (literal translation) dark (in the preserved object it is blue-grey) and the lower part light (slightly yellow).  Nearly at the tip of the head towards the lower part (ventral side) and totally isolated from the mouth opening, are two nostrils in a distance of 2.1 cm and 1.4 cm, respectively, from each other, both are partly obscured by small triangular nasal flaps.  Close under them, relatively parallel to the main axis of the cone-like head one gets to the mouth opening.  It is big and, as a cut parallel to the headcone, it is half-moon-shaped.  Although the blunt tip of the head, the rostrum, is protruding a small bit over the mouth, one can still call the mouth opening with a bigger right terminal, because the opening lies towards the front, therefore when viewing the embryo it can be seen directly on the tip of the head.  This would not be the case if it would lie, as described (indicated) by Günther, towards below, which can be observed as an extreme in Mustelus laevis. 

 

Fairly (somewhat) over the corners of the mouth and a small distance after the nostrils one finds the relatively large eyes.  In the outer skin they build a circular cutting with a diameter of 1.2 cm  and 0.8 cm ,respectively, which, in the case of the smaller objects due to the preservation, can not be guessed as such that easily[5].  Even with the most meticulous investigation, no nictating membrane could be discovered. 

 

The head goes (changes) without any interruption (pause, break) into the neck, which has the same colour like the head and which possesses 5 relatively wide gill slits on either side.  They are in front of the pectoral fins and reduce their size towards the back.  The width of the first gill opening is nearly the same as the distance from the first to the last gill slit.  The foremost gill slits go so far towards the ventral side that they come close to its middle line.  The length of the foremost gill slits is 4 cm and 5.5 cm, respectively, those of the back, the smallest, 2.5 cm and 3.2 cm, respectively. 

 

The position and the whole external features of the gill slits already give, after Jaekel (1890), a small hint towards the families our embryos may belong and to which they will not.  After Jaeckel’s statement they can not belong to the families of Carcharhids (in contradiction with Braus’ assumption) and Scylliids and Cestracion.  In those, one finds five short gill slits of which the foremost ones sit in front of the pectoral, the rear (posterior) ones over the pectoral fin.  Also, the foremost ones reach down to the insertion point of the pectoral fin.  In some forms (species), the last slit seem to be built back (literal translation), or  is so close to the second last that it is externally barely visible next to the second last, therefor one sees only four gill slits.  Of those, there are then only two situated before the pectoral fin.  The same way we found the gill slits in our embryos was found by Jaeckel in the Lamnids and Spinacids including Pristiophorus, in which always all openings are in front of the pectoral fin, mostly very long and reaching below the basis of the pectoral fins. 

 

In our Lamni one has difficulty to find their squirt holes (spiracles ?).  When one very carefully examines, one can find on both sides, approximately in the middle of the connecting line between the back  (posterior) edge of the eye and the topmost corner of the first gill slit, each one pore-like depression.  Both embryos have them in the same position, which perhaps disappear completely in the fully grown animal.  They do not seem to be deep as we could only insert a probe for a little bit.  With a cut they disappear very quickly under the surface[6]. 

 

The cylindrical-shaped torso is approximately twice the length of the head and neck and becomes smaller towards the end.  On the upper part and lower part (dorsal and ventral) it also has the same coloration as the head and neck.  Whereas those two colorations slowly merges into each other, at the back (posterior) part of the torso, they are sharply separated on both sides with a keel. 

 

Of most selachii is known that their dorsal area shows a certain amount of roughness due to a number of “skin teeth” (literal translation).  Now, our embryos were investigated for those placoid scales (literal translation). Dyed (stained) cuts were made from part of skin pieces and some of those pieces were treated with warmed, concentrated potash (caustic lye).  But neither the cut series nor the treatment with potash showed apparent skin teeth. 

 

The light coloration of the belly side merges on to the egg-like yolk stomach, on which the embryo sits from the middle of the neck to the middle of the torso, till the anal opening.  The, as a result, missing umbilical cord and the significant size of the yolk stomach leave our Lamni, as also mentioned by Doflein himself, different from all, to date, known shark eggs. 

 

Directly behind the last gill slit and behind the lower edge sit the two pectoral fins.  They build a triangle with a rounded tip and a slightly cut out posterior edge.  As the front edge is slightly bent, the whole fin appears slightly curved.  Both edges are only a little bit longer than the base.  The pectoral fins can not be called particularly big.  Their lower part is coloured very light and the upper part grey with the exemption of the lighter edges. 

 

Above the backmost (posterior) end of the pectoral fins starts the first dorsal fin.  Its front edge builds a blunt, rounded angle with the back area, its back edge a pointed angle.  It has nearly the same form than the pectoral fins, only one third shorter.  It does not have a spine.  Its colour is white-yellow: only the free edges appear grey. 

 

Approximately two lengths[7] behind the dorsal fin, directly behind the insertion of the yolk stomach, begins the completely lightly coloured belly (pelvic) fins.  They have half the length of the pectoral fins and the shape of an elongated rectangle.  The one pair of small sides are grown on (the torso) close to each other, so that the inner, parallel lying broad sides tightly confine the front halves of the anal opening[8]. Those inner long sides are in their back half bent (scalloped) slightly towards the anus.  The outer long sides, however, proceed parallel to the just mentioned inner ones, so that the whole pelvic fins assume a bent (scalloped) form.  In addition, the free edges are rounded and the free short sides are cut out slightly round.

 

Approximately in the same distance, in which the first dorsal fin is distanced from the tip of the snout, we will meet - behind the first of the second dorsal fin and exactly opposite it, the anal fin.  Both are very small and the same in shape and of light coloration.  They have the shape of small rectangles, their attached (grown on) edges are one third smaller than the base of the first dorsal fin.  Their edges are straight and build with the dorsal and belly line, respectively, one frontal blunt and one posterior pointed angle. 

 

The body goes gradually into the tail, which is divided distinctively by a keel into an upper and a lower part.  A short distance after the second dorsal fin, the tail broadens into the tail fin.  It consists of an upper and a lower lobe, the lower lobe is half the size of the upper lobe.  Both build a pointed angle to one another.  At the root of the tail fin there is, dorsal and ventral each, a distinct groove or scar impressed (precaudal notch ?).  The lower lobe is short and broad with rounded edges and sides, with the tip pointing back.  The upper lobe, on the other hand, is long, with a broad basis and pointed towards the back.  Shortly before the outermost tip, it has a triangular cutting.  Also, the whole upper lobe is bent sickle-like.  Both lobes are light in their coloration.  Only the outmost edge of the lower lobe is dark grey, nearly black in colour, whereas the same edge of the upper lobe appears faintly grey. 

 

Measurements

Small  Big

                                                       specimen  specimen

                                                            cm            cm

 

Total length of the embryo............................. 42.8    55.3

Width of the embryo (at the location of the yolk stomach        5.6  6.3

Longitudinal axis of yolk stomach...................... 14.9    21. 1

Lateral (or transverse) axis  of yolk stomach.......... 9.5     12.3

Distance between mouth ends............................ 3.8     4.2

Distance between nostrils.............................. 1.4     2.1

Diameter of eyes....................................... 0.8     1.2

Distance between the first and the last gill opening... 3.6     3.8

Distance between the tip of the head and the yolk stomach       8.9  12.4

Distance between the tail tip and yolk stomach......... 21.1    26.7

Distance between tip of head to first dorsal fin....... 13.1    17.8

Distance between first dorsal and second dorsal fin.... 12.3    17.8

Distance between tip of head to pectoral fins.......... 9.7     13.9

Distance between pectoral fins and pelvic fins (anus).. 9.7     13.1

Distance between pelvic fins and anal fins............. 5.3     6.5

Height of the first dorsal fin......................... 2.1     3.2

Length of the first dorsal fin......................... 2.5     4.3

Length of the second dorsal fin........................ 1.3     1.7

Length of pectoral fins................................ 3.5     5.4

Length of  pelvis fins................................. 2.2     2.9

Length of anal fins.................................... 1.4     1.8

Length of tail fin (upper lobe)........................ 11.5    14.7

Length of  tail fin (lower lobe)....................... 5.4     8.2

Base of the first dorsal fin........................... 2.5     4.3

Base of the second dorsal fin.......................... 0.7     1.0

Base of pectoral fins.................................. 2.1     3.0

Base of pelvic fins.................................... 1.0     1.6

Base of anal fins...................................... 0.7     1.0

Base of tail fin....................................... 1.4       1.8

 

III.  Situs viscerum (the position of the intestines ?)

(Fig. 4-6.)

 

In order to get to the internal organs, the peritoneal cavity was opened from the right side and at the position where the embryo and the yolk stomach merge into each other.  The resulting skin flap can easily be flapped back over the yolk stomach as Figure 4 shows.  That is (because), the external skin of the animal does stretch around the yolk stomach, without being somehow fused (grown together, attached) with it.

 

Most conspicuous, the enormous bloated yolk stomach (do) steps into forefront view.  Even now its red-yellow colour is conspicuous, which indicated the presence of a plentiful amount of yolk mass.  Also, a number of stronger blood vessels (g), which appear in the preserved state white, are clearly recognisable in the wall of the yolk stomach.

 

As we are cutting open, already the right liver lobe, which still lies a small amount over (on top of) the yolk stomach, is coming towards us from askew under the right pectoral fin (Br).  From the still partly obscured peritoneal cavity protrudes, under this liver lobe, the spiral intestine (s).  Already, this piece, that reaches from the liver lobe till the pelvic fins, gives an indication as to the size of the spiral intestine, one can already see clearly from the outside its internal spiral-flap (valve) building.  In a quite short distance and parallel to this spiral intestine stretches out (draws out, drags out) a second part of the intestine (p), which also emerges under the liver lobe, (then) stretches out (draws out, drags out) over the yolk stomach and suddenly disappears from the surface (m. p.) shortly before the pelvic fins (Ba.).  Later, more detailed investigation will show that at this point it leads into the yolk stomach.  It will be established as the ascending part of the stomach.  On it is attached , along the whole side of the spiral intestine, an organ (m), elongated and partly divided into smaller pieces, which is nothing else than a branch of the still to be mentioned spleen.

 

If we proceed with the above mentioned cut on the left side, one can see the following picture (Fig. 5): underneath the left pectoral fin, completely analogue to the right, protrudes the left liver lobe and lies also partly over the yolk stomach.  This (yolk stomach) fills, of course, here also fully the opening caused by the cut, and it is also recognisable here by is richness in yolk mass and blood vessels (g).  But, where at the right side the spiral intestine and the second into the yolk stomach leading part lies, lies here an organ, that divides (falls apart into pieces) into many small parts.  It is the spleen (m), which is divided into many small spleens, as has already been observed in some sharks.  In our Lamni it lies partly left, partly dorsal- area-like on the yolk stomach till to the spiral intestine, goes around its (intestine) back part in a circle and sends the already mentioned branch to the ascending part of the stomach (m).

 

This whole assembly of the internal organs seems different compared with other sharks.  The organs have mainly an unusual position, which is only, and only, caused by the yolk stomach.  If one compares the situs viscerus of an older embryo of Mustelus leavis, the following picture emerges: both enormous liver lobes protrude (emerge) underneath the pectoral fins.  They have to be put aside a considerable part to fully see the other organs.  The other organs are in a row from left to right as follows: the spiral intestine stretches out (draws out, drags) from the cloaca nearly the whole length of the peritoneal cavity.  Shortly before the root of the right liver lobe it turns around (pylorus) and flows into (merges into) the ascending, thinner parts of the u-shaped stomach.  Along this section runs on the side of the spiral intestine the spleen, which is quite small till the back part of the ascending stomach shank (part), but forms itself at the knee of the u-shaped stomach into a broader organ.  Under the pylorus, one can see to a small degree the pancreas which then disappears behind the spiral intestine.

 

If one imagines in this situs the ascending part of the stomach as increasing in extension (size), than there is the question that the other organs would be pressed to the side and to the back.  This would then show the picture which the situs viscerum of our Lamni is showing (Fig. 4-6).

 

IV.  Digestive tracts

(Fig. 8-21.)

 

a) Mouth (Fig. 8-10.)

 

As we saw earlier on, the mouth of our shark lies quite at the end of the head.  His size can draw the conclusion of the later (evident) greediness (voracity) of the Lamna species, which (the conclusion) is strengthened by the few, but externally visible, teeth.  The upper and the lower jaw, both half-moon shaped, are externally nearly  smoothly covered with the skin and there is only a slight hint of lip building (Fig. 12 li) to observe.  However, on the insides of both jaws the skin widens (expands) to lumps (swellings, humps, folds), which snuggle up closely to the jaws and which hide the young developing teeth[9] under them.  One can easily rip them (the folds) off their attached sites and thus make the young rows of teeth visible.  The latter is only possible if one - in the process - rips off the tooth ridge[10] from the young teeth.  Thereafter, those skin folds build the developing teeth themselves.  Those folds elongate themselves into the inner part of the mouth (throat) to the inner mouthwrinkles (literal translation, mouth folds).  The mouthwrinkle of the lower jaw (mu) is relatively insignificant, whereas that of the upper jaw reaches nearly to the middle of the mouth (throat).  In this way, the mouth (throat) is closed bag-like with a relatively closed mouth.  One can make the speculation that this arrangement prevents the yolk stomach to get outside.  Because in our Lamni the yolk stomach is a substitute for the stomach, there is easily the possibility that, through pressure or other reasons, the yolk mass is emerging through the short oesophagus into the  mouth cavity.  But here, this mouthwrinkle acts as a flap and prevents the yolk mass to get outside.  In later life in particular this fold will  be responsible to prevent the return (retreat) of swallowed water from the mouth cavity. I have found the mentioning of a similar mouthwrinkle (fold) only once and this in “Müller and Henle,  Systematic description of plagiostoma” (1841) where in the family of Alopeciae a “mouth fold/wrinkle” is mentioned.  But more information about its form and function is missing completely.

 

Stannius (1846, p.  88) attributes mucous membrane folds (literal translation), lying behind the jaws, to many teleosts, which prevent the return of swallowed water from the mouth cavity.

 

Amongst the histological  nature of this fold is remarkable, that the epithelial cell layer of the dorsal side is nearly three times thicker than on the other side.  One can also observe in this cell layer bud-like clusters of cells.  They are similar to taste buds, unfortunately the preservation is not such that one can declare with confidence the presence of taste buds and examine the buds closer.

 

The broad gill slits (ksp), which externally reach already pretty far to the middle of the neck, leave free in the inside of the mouth an even smaller middle piece.  Their width also, is equal to the broad external gill openings[11]. 

 

In front of the first gill slit rises the tongue (zu) which is far bigger in our specimens than one would be used to from fishes.  The fish tongue is known as a mere rudimentary (thing) of a tongue and as completely immobile (Hörschelmann, 1866).  But the tongue of our Lamna is surely not completely without function; because in sagittal cuts one discovers a supporting cartilage (Kn) which is developed far to the front.  On it adds on a broad muscle (mus), which, without doubt, enables no small movability of the tongue[12].  For a conscious[13] movement vouches the distinctively developed lateral stripes of the muscle.

 

The big throat, which rather suddenly narrows itself into the oesophagus is lined with mucous membrane of the mouth.  This is, as evolution shows, nothing else than the external skin and as such it could carry the - for sharks peculiar - skin teeth (dermal denticles).  Now, we have not found on our two sharks any sign of dermal denticles in the external skin, so that therefore we can assume that there are also none in the mucous membrane of the mouth (buccle mucous membrane ?).  And really, there are no developed dental teeth in it.  On cuts through the buccle mucous membrane, however, one finds peculiar, wart-like forms (Fig. 9 and 10 hz) which are protruding from the epidermis and which one must see as back-developed skin teeth.  They are distributed in irregular distances on the skin and are partly with one hump, partly with two humps.  That such forms have been found in some sharks is mentioned , e.g., by Hertwig in his paper “On the structure and development of placoid scales and the teeth of selachii” (1874) where he writes: ”According to Leydig they (the skin teeth in the mouth) occur also, apart from Hexanchus, in Raja clavata, but have on the other hand not been found in Scyllium and Scymnus.  Here they are  substituted by wart-like or filament (cord-like), non-calcified papillae, which have the same triangular form as the teeth of those animals and which would represent completely developed teeth if they would be covered by a cap of calcium salts”.

 

b) Teeth (Fig. 11-12.)

 

The second type of teeth in the buccle mucous membrane is restricted to the upper and lower jaw.  Although those differ only a little from the so far described selachii teeth, they should be described here for completion’s sake.

 

In our two Lamnids, the number of externally visible teeth is still very low (Fig.  8).  However, they give information on their form and arrangement which is important for the later taxonomic determination. 

 

It is, however, as difficult as it is brave to use those teeth of -granted nearly fully developed- embryos too strictly (rigorously) in a systematical determination.  This will also be considered later in the taxonomic determination of the species of our Lamni.  The present teeth are mainly irregular distributed in both jaws; a regular arrangement in rows is not visible yet.  Some are protruding completely, whereas others are only partially visible.  But even those few teeth give a clue to the later strong set of teeth (denture).  Close to the symphyses (Fig 8 sy), which are externally visible marked and which do not carry any middle teeth, different circumstances attract notice.  In the upper jaw, the first two teeth on both sides of the symphysis are markedly smaller than the other teeth of the denture, in particular also smaller than the following third tooth.  After this one a markedly smaller tooth follows, whereas all the following are again bigger.  In the lower jaw this arrangement is not there.  Here, there is only one small tooth on both sides of the symphysis.

 

There are also differences in the form of the teeth.  The oldest are strong, squat (stocky) and markedly awl-like with tips bent backward (Fig. 11 a).  The somewhat younger teeth (b), those which are still sitting in the inner margin of the jaw, show still the awl shape, but are much slimmer and show a lateral flattening. This flattening is completely developed in the even younger teeth which still sit partly in the tooth ridge.  On those, there is not the slightest evidence of awl-shape to detect.

 

The base of the teeth at hand is simple and conical; the two small cusps of other selachii teeth are missing in those teeth.  As all selachii teeth, they are also only embedded with their base in the mucous membrane which covers the jaw arch, they therefore are not connected to the jaw cartilage (Fig. 12).

 

This loose attachment causes a very fast abrasion of the teeth.  The manifold and never-ending supply, however, is provided by many rows of young teeth. One can find in the upper jaw 14 of such teeth rows, in the lower jaw 13, they contain spare teeth in various developing stages.  It was mentioned already that the inner sides of the jaws become visible when folding back the mucous membrane folds.  But to get to know their developmental stages, which is only possible with microscopic preparation, lateral cuts were made through the jaw.  One of the most complete cuts form the lower jaw can be seen in Figure 12, which will inform about nearly everything of importance.

 

Here attracts notice firstly the jaw cartilage (kn), which builds a perpendicular angle and which is bordered by a string of pigment cells (pig).  On its ventral side, close to the edge of the jaw, the connecting tissue shows a distinct, if small, lip building (li), which has been mentioned earlier.  One must therefore agree with Hertwig (1874) and not Jentsch (1897), when he gives the selachii a lower jaw lip.  Jentsch, however, denies this.  In the corner of the jaw cartilage one meets a row of developing teeth (z1 -zb ) in various stages of development.  The young teeth  decrease in age from the jaw edge to the base of the corner ground.  The oldest tooth (z1 ), sitting closely near to the jaw edge, is nearly completely disconnected (literal translation) from the area of the tooth ridge (zl), therefore relatively functional (operational), whereas the other four tooth ridges (z2  - z5 ) still completely protrude into the epithelial ridge[14].  The youngest developing tooth (z5 )  comprises an elongated papilla, over which rises the cylinder-cell-layer (literal translation) of the epithelium (ce) which is filled up densely with mesenchyme cells till close to the epithelium (my).  The next oldest papilla (z4 ) is also covered with epithelium, but is not so densely filled up with mesenchyme cells anymore, in particular at the base.  Also, the latter (mesenchyme cells) do not tower up till the epithelium at the top of the papillae.  In its place a light mass (d) has been built, which shows a visible, but very fine longitudinal striation.  This mass is the fist anlage[15] of the dentine with the manifold dentine canals (ducts) (dentinal, canaliculi dentales ?).  The third youngest developing tooth (teeth) (z3 ) is even more elongated and the dentine is significantly further developed.  It is thickest at the tip and reaches from there down over the whole papilla, whilst it gets thinner as it goes down.  Here also, the dentine ducts appear as a very fine striation.  The next developing tooth (z2 ) is significantly nearer to the fully developed stage.  It is visibly sharpened (pointed) and has already assumed nearly the final form.  The dentine (d) has also experienced a significant change.  It has broadened in the whole papilla till the base in the form of dentine cords, which show between them broad dentine canals (ducts) (dr).  The latter are filled with a number of mesenchyme cells.  This external dentine layer has been stained conspicuously  strong, but only in this anlage, and goes (proceeds) into a remarkably lighter layer (s(v)).  As the light layer at the tooth tip broadens to a summit (literal translation), one can regard this as the layer which is named by many authors as dental enamel, by some others, who deny enamel in shark tooth, as vitrodentin.  This developing tooth is therefore equipped with everything, which the fully developed tooth has.

 

The structure of the developed teeth show small variations from the ones described so far.  That their dentine tubes (ducts/tunnels) are rather wide, has been mentioned already.  They sieve the dentine relatively irregular and go not, as is normally the case, from a distinct centre, the pulpa, in all directions.  Also, they do not branch out as the branches of trees, where they get narrower and finer.  One can not speak of a distinct pulpa in any (of those) teeth.

 

This is already known from several sharks, especially of the genus Lamna.  It is interesting and with this attention is drawn to it, that in this point the genus Lamna is distinctively different from the genus Carcharias.  According to Treuenfels, Jaeckel found that Carcharhids and Lamnids  differ in the structure of the tartar .  Whereas in the Lamnids the dentine small canals come from a multiple branched, net-like pulpa cavity, they take exit in the Carcharhids from a uniform cavity situated in the middle.  This structure is constant in the various teeth forms and separates both families sharply (see remark p. 4).

 

The branches of the dentine ducts (tubes/tunnels) happens in our Lamna such, that directly from the broad dentine ducts (tubes/tunnels) a number of very fine dentine ducts (tubes/tunnels) go off, that the transition is therefore suddenly and does not happen gradually like the branches in the trees.  They are most numerous in the outer dentine layer.

 

c) Oesophagus (Fig. 6.)

 

The wide mouth cavity goes suddenly into a extremely narrow and short oesophagus.  It shows a distinct longitudinal folding, in which some folds protrude as bands with a minimum width of 1 mm.  Its wall (linings) are very thick and lined with very low (short) paving epithelium[16].  On a moderately thick mucous membrane follows a small longitudinal muscle layer and after that a circular muscle layer, four times as thick.  The muscle skin consists, as in all investigated sharks and rays, of lateral striped muscles(striated muscle ?).  In the whole length of the oesophagus, the mucous membrane possesses a quite big number of glands, which one can see in different locations emptying into (leads into) outside.  Several times, the microscopic cuts show those glands without lining epithelium due to the bad preservation and the applied preparation, so that it looks like they are not any glands.  However, in most places they are distinctively lined with epithelium, so that the presence of glands in the oesophagus of the present embryos is without doubt.

 

d) Stomach (yolk stomach) (Fig. 1-6.)

 

The narrow oesophagus goes funnel-like into the descending, enormous widened part of the stomach.  This cardia part (do) is filled bursting with yolk and this is the reason why the name yolk stomach was given.  It substitutes the yolk sack as we will still see.  A proper (true) u-shaped stomach, as it is named in the sharks, is out of the question in our Lamni; because the descending cardia part and the ascending pylorus part (p) of the stomach are very different in their size.

 

The thick wall (lining) of the oesophagus goes into (merges into) the extraordinary thin stomach wall as suddenly, as the oesophagus widens into the stomach. This thin wall (lining) is remarkable for a stomach, but even much more so for the enormous big stomach of our embryo.  One could therefore doubt the firmness (stability) of the yolk stomach, if it would not be enclosed by a firm (stable), external abdominal wall.  Surely, this thin stomach wall will get thicker once the whole yolk mass is utilised and the stomach can assume its normal shape.

 

Despite the maceration one can recognise in most places the circular and longitudinal layer of the muscularis (smooth and striated muscle ?).  A serosa is also there, but a hint of glands is not to be stated.  Only a big number of narrow and wide blood vessels (g) permeate (flow through) this thin skin, which was already mentioned as externally visible.  Surely it would not be completely without purpose that those blood vessels in the present organ appear in this number.  It is with certainty to assume, that these vessels have the function to resorb the immense yolk mass for the feeding of the embryos.  But this is the same procedure as is happening in the yolk sacks of other shark embryos.  Therefore the yolk stomach of our sharks depicts a yolk sack in the common (usual) sense not morphological , but nevertheless physiologically.  It is then explainable, why we could not find glands in the stomach wall, which are redundant in such a nutrition (feeding) at this stage.  They will develop later, when the stomach begins its real function.

 

But how does the amount of food yolk get into the stomach and what is the reason for this interesting case of adaptation, that the stomach takes over the function of the yolk sack?  Those questions are answered by Swenander (1907) who, due to favourable findings, was in a position to give information on the whole state of affairs.

 

During his stay in Trondhjem in January 1904 he got a female Lamna cornubica, which, as it emerged, contained four embryos, two in each uterine division of the oviduct.  Those embryos had a length of 5.5-6 cm and possessed very strongly developed external gills.  What, however, surprised most, was that even in this stadium the yolk stomach was as good as completely vanished.  Externally, there was of it only a hardly millimetre long rest on the stomach (ventral) side present and internally there was only the pitiful remains of the ductus vitello-intestinalis to find.  The feeding canal (literal translation) was nearly completely empty of food.  Apart from these embryos, altogether slightly over 40 things of peculiar shapes were found in the uterus, which proved to be, after closer examination, egg piles enclosed with a common cover (sheat/membrane).  The  cover is relatively thin, but strong and slightly brown.

 

Some time after this, Swenander was sent four more embryos which were taken from a caught Lamna cornubica closely before (out of) Trondhjem.  These embryos had a length of approximately 30 cm, in which they are not even close to our Lamni.  The external gills had disappeared.  The most conspicuous, however, was that they had on the stomach (ventral) side big , round protrusions, which looked after the first glimpse like a slightly removed (detached) yolk sack.  That this, however, was not one, was distinctly evident after cutting this kind of embryo in half.  The mentioned protrusion is very simply a protrusion of the body wall, caused by the outrageously extended stomach.  This one turned out to be filled, including with the oesophagus, in particular with strongly compressed yolk mass.  With closer examination it was shown that in the middle of the yolk mass enclosed in the stomach, there were lying two egg capsules which were still enclosed by their hull.  Those had the same look as the above mentioned.  Herewith the state of affairs was clear with a bang.  The yolk material, which the embryos need for their further development after the, in a very early stage, depletion of the yolk stomach, they get from consumption of the egg capsules lying next to them in the uterus, or their contents.

 

If we would also cut sagitally through our embryos, the same picture would emerge, that Swenander gives about the latter mentioned embryos. Therefore the same situations are evident , which were found by Swenander in the embryos described by him.  As there is not better explanation than that of Swenander, we must also assume for our Lamni, that they loose their yolk sacks at a very early stage, still in the womb (uterus), and so loose all food yolk.  Would they also been born in this period, a further prospering for them would be impossible due to their unfinished development.  But nourishment must be produced, as they stay longer in the uterus.  So they devour the eggs which lay next to them in the uterus and stuff their stomachs full with food yolk.  That the yolk stomach, however, experiences this enormous extension (protrusion), as we showed in the present, nearly fully developed embryos, is nevertheless amazing.  It should also be pointed out, that the yolk stomach has assumed the well developed egg shape.  This is one reason more, that everybody who does not know Swenander’s observations, sees the yolk stomach externally (superficially) as a real (true) yolk sack.  It is therefore explainable when Doflein says, that our two embryos are distinguished from all, to , known shark eggs, by (the fact) that they sit directly on the yolk sack without an umbilical cord.

 

Another case of secondary feeding in shark embryos in the womb in known already in some viviparous sharks.  Johannes Müller (1840) deserves the huge merit, to have proven anew, that amongst the viviparous sharks there are also those where the foetus is intimately connected to the oviduct wall through a placenta.  He named those sharks vivipara cotylophora, in contrast to the vivipara acotyledona, where the embryos have no connection with the oviduct, but develop freely in it.  It is therefore the vivipara cotylophora, where a secondary feeding takes place.  After the yolk mass is used up, the further development of the embryo until the complete formation in the womb is organised through a juice (liquid) exchange between foetus and mother-animal trough a placenta.

 

Should our sharks, and therefore also those described by Swenander (1907), perhaps not formerly have belonged to the vivipara cotylophora?  Should there the development of a placenta not have happened so that, because the mentioned vivipara cotylophora are naturally equipped with a dwindling small amount of food yolk, a new way of nourishment, that is the eating of the neighbouring eggs, was necessary?  It would be interesting if this speculation could be confirmed through later investigations.

 

The investigation of the yolk stomach confirms nearly all statements made on the yolk mass by Joh.  Müller in his paper “On the smooth shark of Aristoteles” (1840).  The yolk mass of our embryos consists nearly completely of globular (spherical) particles (corpuscles), of which only a small number is flattened a little bit.  Internal transverse (lateral/cross) separations (segregations) are not found.  But one can notice of the many granules, as also stated by Müller, that they lie in one cell which contours differ very much from those of the grains and which are very irregular.  Often one observes twin forms in the granules, which are already divided at the edges, but still connected in the middle.  Those also lie scattered (solitary) in cells.  Due to this twin formation and due to the different sizes of the grains, Müller seems to be not wrong, when he sees in this as the developmental stages of the yolk.  The grains divide themselves, after prior twin forming, into smaller granules. The relatively small pylorus part (p) opens on to (into) the lateral (to the side) of the massive cardia parts[17] It lies, as all other organs belonging to the digestive tract, in its whole length flat (flattened) on (top of) the cardia part, so that it is difficult in the first place externally (superficially) to see its opening.  It is, however, immediately visible after picking up the pylorus parts of the stomach.  From it till nearly to the middle, the pylorus part is cylindrical, whereas the remaining part is flattened till the proper pylorus, which could have been caused through the pressure of the organs in their preserved state.  This flattening is, however, basically really without meaning.  It was only mentioned because, at the same place where it enters, the internal longitudinal folding (Fig. 13 lf) dissolves (splits up) gradually into a fine net of folds (furrows) (fn).  This longitudinal folding (Fig. 14 lf) starts already in the cardia part in some distance from the opening place of the pylorus part and extends until the mentioned place, to then built the net of folds.

 

When Leydig says that the part of the intestine lying between stomach and flap (valve) intestine (valvular intestine) - therefore the pylorus part - has a thinner muscle layer than the stomach (cardia part), so shows the microscope from lateral (transverse/diagonal) cuts of the pylorus part exactly the opposite.  The lateral as well as the longitudinal muscle layer (striated and smooth ?) of the mucosa is significantly thicker than that in the cardia part.  The mucous membrane also shows a certain thickness.  It (mucous membrane) builds, especially away from the opening place, several big folds, which again split into many small folds.  The big folds are of course the same which we noticed macroscopic.  Accordingly, the fine net of folds in the anterior pylorus part is build from smaller mucous membrane folds.  Additionally, one finds, in particular close to the opening (aperture) place, a number of oval, sometimes also circular glands in different sizes, of which some distend into a neck and open (into) funnel-shaped.  Those glands are lined with cylinder epithelium till the start of the neck.  According to the statements of Leydig, the stomach glands do not have this cylinder epithelium, he is, on the contrary (rather), differentiating in the latter a sharp contour towards outside and a grain-like-cellular content toward inside.  Both statements do not prove to be right for the material at hand.  If one pursues the mucous membrane with a microscope (microscopically) further towards the pylorus, one observes, that the previously mentioned glands disappear already before the middle of the pylorus. It seems, however, to be possible that, because a strong maceration begins simultaneously with this disappearance, the anterior part of the pylorus has formerly possessed glands.

 

e) Spiral intestine  (Fig. 15-17.)

 

The transition place of the pylorus part of the stomach to the spiral intestine (s) builds, as everywhere, the true (proper) pylorus (py). In the existing case it is narrow and very short, as the spiral intestine descends directly next to the pylorus part in the peritoneal cavity.[18]  At the opening (mouth) place of the pylorus rises in the inside of the valvular intestine a papilla, in its middle focus sits the true (proper) very narrow opening (pap).  Additionally, it should be mentioned that near the external opening place of the pylorus into the spiral intestine the ductus choledochus empties (ends/flows) also into the latter.  From this opening is, however, macroscopically nothing to be seen in the inside of the spiral intestine.  This shall be closer described later in the observation of the liver.

 

The spiral intestine (s) or also named valvular intestine has indeed roughly the same length as the pylorus part of the stomach, but has a significant bigger volume that it.  Already with an external (superficial)  examination it is distinguished by peculiar spiral lines on its surface, which stand perpendicular to the longitudinal axis and which, in the front part, proceed parallel at a distance of 1.5 mm and in the last third  at a distance of 2.5 mm.  Those spiral lines are the places of attachment of the spiral fold, which traverses the spiral intestine in not less than 38 turns (windings).  This is a such a big number of turns, it has so far not been observed in any spiral intestine.  At the same time, the valvular intestine is not very big, at least in comparison to sharks with far longer valvular intestine.  The valvular intestine of our shark has a length of 6 cm and an average (or: at the middle of the intestine) diameter of 2.  5 cm

 

The spiral fold (sf) begins under the opening place of the pylorus, therefore, leaves the valvular intestine free in the frontal part.  This valve-free, above (on top) summit-like covered part of the spiral intestine is named falsely by many authors (e.g., Joh.  Müller, 1844) bursa entiana. Redeke (1900) speaks out on the real bursa entiana speaks.  The further course of the valve is very analogous to a spiral straicase.  Because its width is only 1 cm, therefore smaller than the diameter of the valvular intestine, there is an opening of 0.5 cm in the middle.  This (opening) continues through the whole length of the valvular intestine, so that one can see right to the ground from the top, very similar to some spiral staircases.  In our present spiral fold, however, the opening gets wider towards the end.  The spiral fold decreases in its width from the 28th turn (calculated from the pylorus), so that already at the 32nd turn, it has only the width of 0.5 cm.  At the last turn it measures only 1 mm and goes fairly close to the crossing place (transitional place) in the rectum (colon).

 

According to Joh. Müller, this spiral fold is to be referred to as screw-like.  According to him, the external edge of the spiral valve is attached at the intestine walls like a spiral staircase and its form is screw-like in most sharks and all rays.  The spiral valve of some sharks from the family of the nictating sharks, in particular Sphyrna, Carcharias, Thalassorhinus, Galeocerdo, he calls rolled.  In it, both the attached and the free edge proceed straight from the upper end of the valvular intestine towards below; thereby the valve is rolled around its free edge, which therefore lies in the middle of the roll.  In comparison with our earlier statements it stand immediately to reason, that this rolled form of the spiral fold is out of question in our shark.  Remarkably is only that this from is also found in the genus Carcharias.  This fact (case) gives provisional (temporary) rise to doubt about the correctness of Braus’ statement, that our present sharks  belong to a species of Carcharhids (see section: “External features”).

 

Parker distinguishes four typical main forms of spiral folds.  The spiral fold of our Lamna then belongs to the type A, the simplest form, in which the free edge of the valve proceeds in the same height as the attached edge in all turns.  The width of the valve does not exceeds half of the intestine diameter.  In type B, the valve reaches till the middle of the intestine, whereas in type C and D the latter is exceeded, so that all folds turn themselves backwards (type C) or forwards (type d), respectively.  Both, surface as well as resistance, grows from type A to D.  Therefore both would be present in a very small amount in our present valvular intestine.  Due to the prominent amount of turns of the spiral fold they can equal, perhaps even exceed, the surface and resistance of a spiral fold of one of the other types, but with significant less turns.

 

The surface of the spiral fold and the surface of the inner valvular intestine surface contribute substantially to this.  Even with the magnifying glass one observes on both surfaces of the valve a network of thin small folds (Fig. 17 flt) of the mucous membrane, which builds polygons of different sizes, in particular hexagons and occasionally rather regular ones.  Such small folds are also present on the inner spiral intestine area.  They are as thin as those on the valve, but proceed parallel to each other and are standing perpendicular to the attached edge of the valve.  From this edge they go into (merge into, change into) the mentioned network on the spiral fold.  Those small folds of the mucous membrane, those of the valve as well as those of the intestine area, are at the place of the, in most sharks and rays present, villi[19], of which the microscope does not show the smallest hint in our present animals.

 

Unfortunately, both the valve as well as the intestine wall was very macerated.  One can state rather likely, however, the missing of the glands in both, and one can observe, apart from remains of the muscle layers, the frequent appearance of blood vessels, of which in particular each two could be found regularly at the somewhat widened base of the spiral fold.  These are the branches of the arteria and vena omphalomeseraica, which proceed parallel outwards along the ventral valvular intestine surface and which send a side brach to the left and to the right after each spiral turn.  The same applies to two - also big - blood vessels, which, however, lie dorsally along the surface of the spiral intestine (Fig. 15 g).  They are externally (superficially) not as distinctively visible as the veins and arteries on the ventral side, and it can not be determined with confidence if they also constitute a vein and an artery.  Vaguely visible and therefore not to be referred to with confidence as a real blood vessel, is one such in the free, slightly thickened edge of the valve.  According to many authors such (a blood vessel) is to be found at this place in most rays and sharks.

 

At last it will be mentioned that the valvular intestine was filled up tightly with half digested yolk mass.  Therefore the resorption of the nutrition yolk is not taken care of alone by the yolk sack (stomach), but is partly taken over by the other intestine tract, in particular, however, by the spiral intestine.

 

Not yet translated are pages 18-39:

 

f) Final part of intestine and appendix. (Fig. 6, 15, 18-21.)

 

V. Urogenital system

(Fig. 21-26).

 

VI. Heart

(Fig. 27-29.)

 

VII. Breathing apparatus

(Fig. 30, 31.)

 

Vlll.  Brain and brain nervous system.

(Fig. 32, 33.)

 

Fore brain [telencephalon].

In-between and middle brain [diencephalon and mesencephalon].

Hind brain [metencephalon].

"After" ? brain [myselencephalon].

Cranial nerves.

1. Nervus olfactories.[olfactory or 1st cranial nerve]

2. Nervus opticus.[optic or 2nd cranial nerve]

3. Nervus oculomotorius.[oculomotor or 3rd cranial nerve]

4. Nervus trochlearis.[trochlearis or 4th cranial nerve]

5. Nervus trigeminus.[trigeminal of 5th cranial nerve comprising ohpthalmicus profundus, opthalmicus superficialis, & maxillary branch]

6. Nervus abducens. [abducens or 6th cranial nerve]

7. Nervus facialis [facial of 7th cranial nerve]

8. Nervus acusticus [auditory or 8th cranial nerve]

9. Nervus glossopharyngens [glossopharyngeal or 9th cranial nerve]

10. Nervus vagus [vagus or 10th cranial nerve].

 

IX. Systematic determination

a) After Guenther (1870)

b) After Mueller and Henle (1841)

c) After Hasse (1882)

 

Bibliography

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Borcea, J. 1906. Systeme Uro-genital des Elasmobranches. Arch. de Zoologie Experimental, IV. Serie 4. 1906.

Braus, H. 1906. Zur Entwicklungsgeschichte niederer Haie. Sitzungsber. d. K. Preuss. Akad. d. Wissenschaften, LI, LII, LIII 1906.

Broussonet, M. 1785. Memoire pour servir a l’histoire de la respiration des poissons. Memoir. de L’Acad. d. sciences. 1885.

Burckhardt, Rud. 1907. Das Zentral-Nervensystem der Selachier als Grundlage etc. I. Teil. Abh. d. Kaiserl. Leop.-Karol. Deutschen Akd. d. Naturforscher, Bd. 73, Nr. 2, Halle 1907.

Cuvier, G. 1840. Lecons d’anatomie comparee. II. ed. 1840.

Cuvier et Valenciennes 1828. Histoire naturelle des poissons, tome I. Paris 1828.

Bashford, Dean 1895. Fishes, Living and Fossil. New York 1895.

Doflein, F. 1906. Ostasienfahrt, Erlebnisse und Beobachtungen eines Naturforschers in China, Japan und Ceylon. Leipzig und Berlin 1906.

Droescher, W. 1881. Beitraege zur Kenntnis der histologischen Struktur der Kiemen der Plagiostomen. Inaug.-Dissert. Leipzig 1881.

Duvernoy, G. L. 1839. Du mecanisme de la respiration dans les poisssons. Annales des sciences naturelle. 1839.

Edinger, Ldw. 1877. Ueber die Schleimhaut des Fischdarmes. Arch. f. mikrosk. Anat., Bd. XIII. 1877.

Gegenbaur, C. 1866. Zur vergleichenden Anatomie des Herzens. Jen. Naturw. Zeitschr., tom. II. 1866.

Gegenbaur, C. 1872. Untersuchungen zur vergleichenden Anatomie der Wirbeltiere. III. Heft, “Das Kopfskelett der Selachier”. Leipzig 1872.

Gegenbaur, C. 1878. Bemerkungen ueber den Vorderarm niederer Wirbeltiere. Morph. Jahrb., IV. 1878.

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Heinecke, Fr. 1873. Untersuchungen ueber die Zaehne niederer Wirbeltiere. Zeitschr. f. wissenschaftliche Zoologie, Bd. XXIII. 1873.

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His, W. 1893. Vorschlaege zur Einteiling des Gehirns. Arch. f. Anat. u. Phys., Anat. Abt. 1893.

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Xl. Figure captions.

 

Fig. 1.  Larger Lamna-embryo.  (1/2 nat. size.)

Fig. 2.  Smaller embryo.  In natural position. (Ca. 1/2 nat. size.)

Fig. 3.  Smaller embryo.  In stretched position. (Ca. 1/2 nat. size.)

A = anal fin; Ba = pelvic fins; Br = pectoral fins; Do = yolk stomach; Gr = precaudal pit; ki = caudal keel; ksp1-5 = 5 gill slits; md = mouth; na = nasal aperture; o = eyes; R1  = 1st dorsal fin; R2  = 2nd dorsal fin; Sch = caudal fin.

 

Fig. 4.  Viscera, right lateral view (2/3 nat. size).

Fig. 5.  Viscera, left lateral view (2/3 nat. size).

Fig. 6.  Intestinal tract with raised spiral valve (2/3 nat. size).

a.o.m. = omphalomesenteric artery; app = appendix; Ba = pelvic fins; Br = pectoral fins; Do = yolk stomach [cardiac stomach filled with yolk]; d. ch = bile duct; e = colon; l = right or left liver lobe; m  = spleen; mp = pyloric stomach opening [from yolk stomach]; oe = esophagus; p  = pyloric stomach; [missing py = pyloric valve]; R1 = first dorsal fin; s = valvular intestine (spiral valve).

 

Fig. 7.  (Had to  be deleted!).

Fig. 8.  Front view mouth, wide open.

Ksp = gill slit; mo = buccal fold of upper jaw; mu = buccal fold of lower jaw; ok = upper jaw; sy = sympheses; uk = lower jaw; z = teeth; zu = tongue.

 

Fig. 9. Sagittal section of tongue (x20).

g = vessel; kn = cartilage; hz = recessive mucous denticle; mus = muscle.

 

Fig. 10. Section of mucous membrane in mouth.

ep = epidermis; g = vessel; hz = wartlike recessive mucous denticles.

 

Fig. 11. Teeth of jaw [rather than skin].

a = fully formed tooth [functional]; b = replacement tooth [mis-labled "d"]; c = replacement tooth (was still embedded in dental laminae).

 

Fig. 12.  Cross-section through jaw (with dental lamina). [lower jaw of smaller embryo].

ce = cylinder ephithelium; d = dentine; dr = dentine tubes; kn = jaw cartilage; li = lip formation; my = mesenchyme cells; pig = pigment; s (v) enameloid; z1-z5 = teeth; zl = dental lamina. [z1 has extremely curved crown unlike the replacement teeth still in the dental lamina.  R. Purdy commented that this tooth is similar in form to those found in stem chondrichthyans and that this curvature may be the expression of a primitive character which is lost in later generations (of teeth).

 

Fig. 13.  Transition of longitudinal folds into net of folds in the pyloric stomach.

Fig. 14.  Opening of pyloric stomach from cardiac stomach.

lf = longitudinal folds; fn = net of folds?

 

Fig. 15.  Spiral valve, dorsal view. (1 1/2 nat. size).

Fig. 16.  Upper portion of spiral valve. (opened, 1 1/2 nat. size).

Fig. 17.  Longitudinal section through wall of spiral valve, perpendicular to spiral folds.

app = appendix, d.ch = bile duct; d = colon; flt = mucous fold?; g = vessel; m = spleen; of = openings between spirals?; ov = ovaries; p = pyloric stomach; pa = pancreas; pap = papilla with pyloric valve; sf = spiral fold; sw = wall of valvular intestine [spiral valve].

 

Fig. 18.  Cross?-section of appendix (x50).

Fig. 19.  Longitudinal section of appendix (x50).

Fig. 20.  Longitudinal section of appendix near surface (x55).

Fig. 21.  Cross-section of appendix near opening.

be = cup cells?; cy = cylinder cells; dr = glandular tubes; g = vessels; gg = larger vessels sitting on mucous folds?; mus = muscle layer; sh = mucous membrane; shf = mucous folds; *) part of gland, free of mucous folds and [blood] vessels.

 

Fig. 22.  Part of spleen.

Fig. 23.  Cross-section of spleen.

bi = epidermis of connective tissue.

 

Fig. 24.  Urogenital organs (nat. size).

Fig. 25.  Oviduct and kidneys. Ovaries removed. (nat. size).

Fig. 26.  Kidneys and ureters. Oviduct removed (x1.5).

Ba = pelvic fins; dlw = dorsal body cavity wall; e = colon; eil = oviduct; hbl = bladder; hl = ureter; kl = cloaca, m.eil = opening of oviduct; m.hl = opening of ureter; ni = kidneys; up = cloacal papilla; oe = esophagus; ov = ovaries.

 

Fig. 27.  Heart with branchial arteries. Ventral view (x2).

Fig. 28.  Heart.  Dorsal view.  The auricle is dissected and bent back (x2).

Fig. 29.  Conus arteriosus, opened (x6).

1a-5a = 5 branchial arteries; co = conus arteriosus; d.c.d = duct of Cuvier, right; d.c.s = duct of Cuvier, left; k = ventricle; ka = opening of the 5 branchial arteries [not used in any figure?]; m = thickened middle part [of pocket-like valves]; m.s.v = sinu-auricular opening; mtr = network of muscles? o.av = auriculo-ventricular opening; s = thinner lateral part [of pocket-like valves]; sef = tendinous chords; skl = sinu-auricular valves; s.v = sinus venosus; v = auricle (atrium); va.d = right sinu-auricular valve; va.s = left sinu-auricualar valve; zw = accessory valves; I-III = transverse rows of valves; I = pocket-like valves; II, III =  tongue-like valves;

 

Fig. 30. Diaphragm [gill pouch or pocket] of 1st and 2nd gill slit on right hand side.  Posterior surface, gill plates removed (nat. size).

Fig. 31. Cross-section of gill wall, perpendicular to the longitudinal axis of the plates (ca. x 50).

baw = Balkenwerk?; bl = gill filaments; bla = afferent branchial arterioles; blv = efferent branchial arterioles; ep = epibranchial with cartilaginous branchial rays; kb. a = branchial arch artery. branchial afferent arteries, arterioles are shown in black for clarity; ker = ceratobranchial with cartilaginous branchial rays; kh = extra-branchial cartilage originating at hypo-branchial; kn = button-like end of gill filament [containing efferent branchial arteriole]  kp = extra-branchial cartilage originating at pharyngo-branchial; m. add = adductor muscle; m.c = constrictor muscle; m. i = interbranchial muscle; n.a = nerve branches?; shf = small mucous membrane folds, dissected irregularly.

 

Fig. 32.  Dorsal view of brain (x4).

Fig. 33.  Ventral view of brain (x4).

V = telencephalon; Z = diencephalon; M = mesencephalon [optic lobes]; H = metencephalon [cerebellum]; N = myelencephalon [medulla oblangata & restiform bodies].

Cranial nerves: n.2 = optic; n.3 = oculomotor; n.4 = trochlear; n.5 = trigeminal; n.6 = abducens; n.7 = facial; n.8 = auditory [octaval]; n.9 = glossopharyngeal; n.10 = vagal.

 

boc = eye ball; cr = restiform bodies; et = eminentiae teretes; hy = pituitary gland; hyst = epithalamous; li = infundibulum [& asssociated structures?];  lo = olfactory bulb; ltr = lobi trigemini; p.p = ophthalmicus profundus branch; p.s = superficial ophthalmic branch; rmm = maxillary branch [of trigeminal]; r.v.t = regio ventriculi tertii; sla = sulcus longitudinalis anterior; slp = sulcus longitudinalis posterior; sv = vascular sac; to = olfactory tract [or peduncle].

 

Fig. 34. Median, perpendicular cross-section of vertebrae (x6).

a = outer zone; cd = centrum; fc = notochord; h = haemal arch; i = inner zone; n = neural arch; st = calcified rays [spokes].

 



[1]This is the literal translation. I do not know  if this means just “big shark” or if it is an old German species name.

[2]The German text means either he got the specimens to determine them, or he got the determined specimens.

[3] I don’t know what this abreviation means in English.

[4]Lohberger has a footnote here saying: “We will see later in the taxonomic determination if it is really a Carcharhid species.”

[5]I think he means that the eye can not be seen that easily in the smaller specimen due to preservation.

[6] The meaning here is not clear in German, either they sectioned it poperly or they just cut at the head.

[7] The original text doees nor say what type of lenghts.

[8] I don’t understand that sentence even in German.

[9] I couldn’t get an accurate translation for this term. According to the dictonary the translation is “tooth anlage”. Anlage according to s dictonary of biological terms is German and means the 1st structure or cell group indicating development of a part or organ.

[10] I do not know what is meant by the German word (“leiste”), therefore I could not find a proper translation. Could be moulding, ridge, ledge, “carina”. I could mean that in which the row of teeth is found.

[11] I think he means that the width is the same internally and externally.

[12] He means that this muscle enables quite a moveability of the tongue.

[13]The literal translation means arbitrary, but I think that “conscious is what he means.

[14] Again the same problem with the translation of the word “leiste”. I opted again for ridge.

[15] See footnote 9.

[16] Again, as I don not know the different types of epithelium both in German and in English; this is a literal translation.

[17] The original test has plural here.  It can however also bee seen as the ancient form of the singular dativ.

[18] Or: as the spiral intestine directly next to the pylorus part descends in the peritoneal cavity.

[19] I think he means villi on a biger scale than the microscopical scale.