308 PROCEEDINGS OF THE ACADEMY OF [1896. THE MESENTERIES OF THE SAURIA.i BY E. D. COPE. Examination of the literature shows that this subject has been nowhere adequately treated. The most considerable paper is one by Dr. F. E. Beddard in the Proceedings of the Zoological Society of London for 1888. This, however, includes an examination of a limited number of genera, (eight) only. The present paper is founded on a study of most of the genera of all the families, except- ing in the cases of the Gecconidse and Agamidie, where my oppor- tunities have been more restricted. I am indebted for this material to the U. S. National Museum, the collections of the Academy of Natural Sciences of Philadelphia and my own. A fold suspends the alimentary canal from the median dorsal line, forming the dorsal or epigastric mesentery (E G). No other mesen- teries bind the alimentary canal, except the stomach, and sometimes the adjacent portion of the small intestine, which have other connec- tions. The liver, on the other hand, has several mesenteric connec- tions, as follows : Its ventral face has usually a single sheet connect- ing it with the median ventral line, but in rare instances it is bifurcate posteriorly (Scincidffi generally), or even double (Tiliqiia, LHV, RHV). This sheet, or one of them, is continued along to the ante- rior abdominal artery to the ventral wall, and sometimes along the gall-duct to the pyloric part of the small intestine. Each border of the liver is twice or thrice concave above, in adaptation to the stomach and lungs in the types where the latter extend so far poste- riorly, which is the usual arrangement. From the left hand ridge thus produced, a sheet or mesentery extends to the stomach, form- ing the gastrohepatic mesentery (GH). It is sometimes median in position. From right hand superior angle a mesentery ex- tends to the right dorsal body wall, forming the right hepatic mesentery. The four mesenteries now described are the only ones which are universally present, which bind the liver. The following sheets are present in various types. Frequently the right hepatic and the gastrohepatic give off sheets to the right ' Read before the American Association for the Advancement of Science, Springfield meeting, Aug. 30th, 1895. 1896.] NATURAL SCIENCES OF PHILADELPHIA. 309 and left lungs respectively, constituting the right hepatopulmo- uary and gastropulmonary mesenteries (RHP. and GP.). A sheet occasionally goes off from the gastrohepatic to the left body wall, forming the left gastroparietal mesentery. This is frequently represented by a narrow band, and occasionally, as in Dipsosaurus, it joins the small intestine just beyond the extremity of the gastro- hepatic sheet. This is not represented on the accompanying dia- gram. In Heloderma a distinct sheet extends fi'om each border of the liver to the body walls, forming the right and left lateral hepatic mesenteries (LLH, RLH). In Chamceleon, Polychrus and Anolis, the left lung besides being attached to the gastrohepatic mesentery, is attached by a sheet to the left border of the liver, forming the left hepatopulmonary mesentery, (LHP). Diagram of peritoneum of Sauria, with all the folds displayed by a transverse section near the middle of the liver. L liver ; St. stomach : E.L right lung; LL left lung; EG epigastric, peritoneal fold; LHV and RHV, left and right hepatoventral folds ; RLH and LLH, right and left lateral hepj^tic folds; KH, right hepatic; GH, gastrohepatic; LHP and RHP left and right hepatopulmonary folds. In Varaiius salvator there is a short median gastrohepatic sheet (GH). In Varanus, owing to the anterior position of the lungs, they have no hepatic or gastric connections. In no Saurian have I observed a right hepatopulmonary sheet, as the right hepatic mesentery supports the right lung. The latter extends along the apical strip of the right lobe of the liver to the genital mesentery in many genera. In Tupinamhis, Dracoena, and some others, the right hepatic extends as a strong sheet to the right body wall, forming with an equally strong gastroparietal of the left side, a kind of dia- 310 PROCEEDINGS OF THE ACADEMY OF [1896. pliragm. In many genera, the right hepatic sheet is connected with the stomach, especially at its proximal part. Besides the hepatic and gastric mesenteries, there are those which enclose the internal genitalia, the urinary bladder, and the corpora adiposa. The genital mesentery is sometimes quite extensively free, and is always so anteriorly, especially where it supports the wide fontanelle of the oviduct. A mesenteric pouch encloses the corpora adij^osa, only in those forms where those bodies project freely into the abdominal cavity, as is frequently the case. The cystic mesentery is a transverse fold of the peritoneum whicli lines the inferior wall of the pelvic cavity, which encloses the urinary bladder, when it is present. Beddard has stated that in the genus Varanus there is a " hori- zontal sheet" of mesentery between the viscera and the abdominal peritoneum. This is an interpretation of the fact that the abdominal peritoneum is loosely attached to the abdominal muscular sheaths, and is readily separated from them. This sheet, however, presents the usual relation of the abdominal peritoneum to the viscera, as Beddard states, and appears to me to be homologous with it.* The same condition caused Giinther^ to state that in Regenia ocellata the corpora adiposa are enclosed in " a separate sac of the peritoneum," whereas the former are not enclosed in a special sac as in some other genera. In the Chamseleonidae the mesenteries include the usual hepato- ventral, epigastric, gastrohepatic and right hepatic, the last includ- ing the right lung. The left lung is included in a left hepatogastric, a feature seen in few other groups, notably in the Anoline Iguanidre. There is also a left hepatolateral, from the liver to the left body wall, having a direction diagonal to the long axis of the liver in C. basiliscus. In the Nyctisaura I have been able to examine the mesenteries in relatively few genera of the superfamily. I find in both Gecconidae and Eublepharidse the structure to be of the type most frequent in the Sauria ; i. e. ; a simple hepatoventral ; a single gastrohepa- tic ; a left gastropulmonary ; and a right hepatic which embraces the right lung. In the Agamidse the mesenteries present the usual sheets, hepato- ventral, gastrohepatic, left gastropulmonary and right hepatic, 'Proc. Zool. Soc, London, 1888, p. 98. 'Loc.cit., 1861, March. 1896.] NATURAL SCIENCES OF PHILADELPHIA. 311 which includes the right lung. I have noted the following modifica- tions : In Agama colonoram the left gastropulraonary has become a right gastrohepatic by its continuing to the liver, a character ob- served in Chamceleon and the Anolinse. There is also in this species a left hepatoraarginal. In Megalochilus auritus there is a right hepatoventral, as in Phrynosoma. In the Iguanidae the hej^atic mesenteries conform to the general type, with certain exceptions to be mentioned. Thus there are no right or left lateral hepatic mesenteries, and but one ventral. The right hepatic supports the right lung. There is frequently a rudi- mental right lateral hepatic which connects the long right apex of the liver with the right body wall. There is a gastrohepatic which generally spreads over the space enclosed in the bend of the stomach. There is no left gastroparietal sheet or band. The most remarkable deviation from this type (which I have verified in twenty genera) is found in the Auolinie. Here the left lung, besides its superolateral connection with the stomach, is connected by a special sheet with the left part of the inferior face of the liver. Thus the latter organ is suspended by two sheets to the left side of the middle line. In genera where this is the case the two sheets are sometimes difficult to distinguish owing to their easy adhesion together. They may be separated by inserting a probe from the free caudad extremity of the lung. Another variation from the normal type is seen in the presence of a right lateral hepatic sheet in Phrynosoma and Polychrus (in Poly- chrus gutturosus it is wanting in the one specimen examined). A left lateral sheet is present on the cephalad half of the liver in Cyclura cornuta and Polychrus marmoratus. It is rudimental in Polychrus aeidirosiris, and wanting in P. gutturosus. There is a gastroparietal band in Cyclura cornuta, which is joined by the apex of the peritone- um of the corpus adiposum. In the Anguidse the viscera do not display any exceptional features, except as to the serpen tiform genera. The mesenteries are of the typical character, modified in Ophisaurus by the reduction of the left lung. The hepatoventral sheet is very near the left margin of the liver in Pseudopus apus, and the gastrohepatic and right hepatic are near together when slack. ^ In the Helodermatidse the mesenteries of Heloderma are charac- teristic. There is a single hepatoventral, and the gastrohepatic has the usual position. The right hepatic goes to the right side of the 312 PROCEEDINGS OF THE ACADEMY OF [ISOS"^ Stomach, becoming a right gastrohepatic, and does not extend to the dorsal peritoneum, a character in which it is unique in the Sauria. Posterior to the middle of the liver they unite on the middle line, as in the Teidte. The lungs are attached to the adjacent parts of the gastric peritoneum by separate sheets, the right and left gas- tropulmonary. Besides these there is a strong sheet on each side extending from the superior side of the liver near the border, to the body wall, forming the right and left hepatolateral. The right hepatolateral does not extend along the right border of the liver beyond the cephalad half. The right gastrohepatic continues along the elongate right process of the liver to the genital fold of the peritoneum, and the apex of this process of the liver sends a recur- rent sheet backward, which forms with the former, a funnel-shaped passage. This recurrent sheet might be regarded as a caudad hepatolateral. Dr. Shufeldt states* that Heloderma possesses the free ventral peritoneum found in Varanus, but this is not the case, as this structure is the usual one. The peritoneum forms a transverse fold at the posterior part of the corpora adiposa, supporting the urinary bladder, and forming the cystic mesentery. It is but loosely attached to the corpora adiposa, which do not project freely from the body wall and hence have no special peritoneal pouch. They are elongate and coarsely sub- divided. In the Zonuridre the mesenteries in the genus Zonurus are of the usual type. There are one hepatoventral, a gastrohepatic, a left gastropulmonary, and a right hepatic which encloses the right lung. The mesenteric attachments of the liver are very characteristic in the Teidse. There is but one suspensor, a median gastrohepatic, but this bifurcates above the middle of the organ, and each half diverges, and adhering to the caudad margin, extends to the lateral inferior body wall on each side. In Tupvnmnbis these sheets are united on the median line for a distance posterior to the liver. The lungs are each attached to the stomach by a separate sheet. The left hepato- parietal sheet is always present in this family, but the right one is feeble in some genera, and is easily ruptured, as for instance in Cnemidoplioriis. I have examined the genera Draccena, Tupmam- bis, Callojmtfis, Amiva, Cnemidophorus, Centropy.v, Tejus, Anadia and Oreosaurus. * Proceeds. Zool. Soc, London, 1890, pp. 193-4. 1896.] NATURAL SCIENCES OF PHILADELPHIA. 313 In the Scincidse, as in other families, in the serpen tiforra types the liver and stomach occupy a position caudad to the lungs, and so the latter do not appear in the mesenteric connections of the former, e. g, Siaphiis. The mesenteries are the usual ones, but one peculiarity is very frequent though not universal in the family. The hepato- ventral sheet is generally divided into two, a right and left sheet next the liver, forming a pocket which opens caudad. In the Tiliqiia sdncoides the two sheets only unite at the cephalic end of the liver, remaining separate throughout. In the Anniellidse the viscera display the following characters. The left lung is much smaller than the right lung and is proximally fused with it, so that there is but a single lumen. Right lung much enlarged and covering the alimentary canal below (ventrad). Liver considerably posterior to heart, long and narrow, with a small left lobe and a long right lobe extending to the reproductive cells. Gall bladder enclosed by the liver and exposed inferiorly, i. e., occupying a foramen as in the Diploglossa. Alimentary canal distinguished into stomach, and a small and large intestine, without distinct colon. IStomach without curvature ; small intestine moderately plicated, with lacertiform mesentery. Reproductive cells anterior, symmet- rical ; kidneys symmetrical, posterior. There is a single gastro- hepatic mesentery from the middle line of the. liver, and no right hepatic or lateral hepatics. Hepatoventral simple ; plates of epi- gastric very loosely attached together. No pulmonaries at middle of liver. The fusion of the lungs is a peculiarity that I have not noticed elsewhere among the Sauria. The left lung is Irke a diverticulum of the right, and posterior to the point of divergence from the latter is bound to it by connective tissue to the extremity. This fusion is a step nearer to obliteration than occurs in any of the serpentiform genera of Teidse, Scincidse or Anguidoe, where, though of reduced size, it is distinct from the right except at its proximal extremity. In the Amphisbeenidse, as the left lung only is present in this family, there is but one gastropulmonary mesentery. The liver has a crescentic cross-section, and it is supported by two gastrohepatic mesenteries (A7nphisbcena alba and A. fuliginosa), or by only one, and a right hepatic or hepatolateral, as it may be : {Rhineura florid- ana). There is but one hepatoventral. The last described structure also characterizes Euchiroies diporus. 21 314 PROCEEDINGS OF THE ACADEMY OF [1896. Since the above was written a paper has been published in the Proceedings of the Zoological Society of London (1895, p. 702) by Mr. G. W. Butler on the lungs of snakes, Amphisbsenidse, etc. Here the fact of the suppression of the right lung in the Amphisbsenia is pointed out.