ALIMENTARY CANAL OF REPTILES. 



445 



303 



fimbriate. In a Tortoise ( Testudo indica) the inner surface of the 

 small intestine is reticulate : in Testudo tabulata and in the Emys 

 europ&a it is disposed in small and numerous longitudinal rugae : 

 in Chelone imbricata and Chelone Midas the principal rugae have a 

 wavy and slightly zigzag disposition. In the Crocodile the lining 

 membrane of the jejunum is finely reticulate : 

 in the ileum it rises into longitudinal folds : in 

 the colon it again becomes minutely reticulate, 

 and is thrown into irregular rugae. 



The intestinal tube usually somewhat dimi- 

 nishes in diameter as it approaches the colon. 

 The Batrachia have no caecum ; the small in- 

 testine, in the Frog, makes a sudden bend, to 

 terminate obliquely in the short and wide colon. 1 

 The more oblique entry of the ileum into the 

 colon of the Crocodile gives the appearance of a 

 short pouch on one side : some of the circular 

 fibres of the muscular tunic enter the ileo-colic 

 valve. 2 



In the Python the large intestine begins by 

 a subelongate, pointed caecum, marked off from 

 the colon by a plaited valvular fold ; 3 a succes- 

 sion of such folds occurs in the rest of the laro;e 



C5 



gut. Iii some land and fresh-water Tortoises 

 ( Testudo tabulata, Testudo yrceca, Emys europaa) 

 the ileum opens obliquely into the side of the 

 beginning of the colon, leaving a short and 

 simple tf caecal ' summit of that gut ; 4 the mar- 

 gins of the ileo-caacal orifice are puckered into 

 folds, two of which, in Testudo yr&ca, are continued into the 

 colon, the intervening groove extending for a short distance 

 along the curve of the colon. The colon is longer and wider 

 in the herbivorous Tortoises, and usually contains grass, leaves, 

 or other vegetable substances, the small intestines being 

 empty. In some species of Agama {Ardiscosoma), Galiotes, 

 SteUio, Monitor, and in the Draco volans, fig. 303, k, there is a 

 small caecum at the beginning of the colon, ib. i: and this gut, 

 when distended, seems distinguishable from the narrower rectum. 

 But the most complex large intestine has been met with in the 

 herbivorous Iguanas. 5 The ileum terminates by a slit on a ridge 



Alimentary canal, 

 Draco volans. CCL. 



1 xx. vol. i. p. 204, no. 669. 2 Ib. no 670. 3 Ib. no. 671 A. 



3 xx. vol. i. p. 206, no. 671 B. 



1 Ib. no. 671. 



