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Show 200 DR. R. W. SHUFELDT ON [Apr. 1, tion curves round the pancreas, and in it the coats of the tube appear to be thinner than in any other part of the tract. Both the stomach and the duodenum are connected to the spinal column by a broad fold of the peritoneum; in the case of the first it is known as the " mesogaster," and in the second as the " mesentery." These folds are absent in Man. In all of the specimens I have examined, the " ileo-cascal valve " is notably rudimentary in character, and indeed in this form the termination of the small intestine hardly seems to enter into that part of the tract, here spoken of as the rectal pouch, but which in part must also, for its anterior division at least, represent the colon. In Heloderma, too, the blind pouch that represents the ccecum is so shallow that it would hardly attract our especial attention were it not for the fact that it forms quite a conspicuous feature in a number of other species. So far as the general calibre of the intestine is concerned, we are to note that this is the greatest along the duodenal division, and from this onwards to the point where it joins the rectal enlargement the alimentary tube gradually diminishes in its calibre, being very noticeably smaller for the last fourth of its length. It enlarges again slightly just before it terminates. Without giving it a special microscopical examination, the intestine seems to be composed of the usual coats, and upon cutting into it it struck m e that the intestinal villi were comparatively very large, especially along its middle portion. M y big specimen of this lizard had a rectal sac some 9 cms. in length, and of a form that quite well agrees with that of a Lacerta viridis, as figured for us by Professor T. J. Parker in his ' Zootomy,' on page 160 of that work (?•). The mesenteric fold of the peritoneum is continued backwards upon the rectum, and in this region it is spoken of as the mesorectum. From this it will be seen that the entire gastro-intestinal tract is supported, from one end to the other, by a continuous fold of the peritoneum, which latter attaches itself to the spinal column, along in the median line. The blind pouch or ccecum oi the rectum is here very small and scarcely definable. For instance, it is nothing like as prominent as Owen figures it for Draco volans (loc. cit. vol. i. p. 445, fig. 303, h). The Urogenital System.-Unfortunately all the specimens oi Heloderma at present to hand are females; consequently it does not lie within m y power in this memoir to record anything relative to either the urinary system or the generative aparatus in the male. In the urogenital system of the large specimen of this lizard mentioned above the following facts are presented for our consideration. An elongated, large, pear-shaped urinary bladder with thin walls is to be observed. This has a length of 6 centimetres, measuring 2*5 at its widest part, and is supported by the usual tissues, and opens in the usual manner into the ventral wall of the cloaca. Parker (T. J.) found this viscus " bilobed " in Lacerta viridis, but I find no such condition in our present subject, its anterior fundus being uniformly rounded. |