VERTEBRATA. 



79 



marked. The coecum is small in cats, spiral in dogs, and generally 

 absent with the colic valve in the mustelidae. Valvulse conniventes 

 are scarcely developed. 



In thecetacea the tongue is short, thick, fleshy, and but. little sus- 

 ceptible of motion, and in the whale it often affords three barrels of 

 oil. The teeth are prehensile, the salivary glands rudimental or 

 deficient, and the oesophagus short and wide. In the phytophagous 

 cetaceans the stomach is divided into a large cardiac, and a small 

 pyloric portion, by a contraction which gives origin to twotubiform 

 prolongations. The coecum is simple in the dugong, and bifurcated 

 in the manatee. In the zoophagous cetacea the stomach consists of 

 four or five compartments, none of which, except the first, have any 

 communication with the oesophagus, therefore no rumination can 

 occur. The first cavity is small and lined with cuticle, which ter- 

 minates abruptly at the narrow opening leading into the second. A 

 smal| pyloric orifice leads to a dilated duodenum. There is scarcely 

 any distinction between small and large intestine, and the coecum 

 coli is but little developed. Why so complicated a stomach should 

 exist in animals nourished by the most digestible and highly organ- 

 ised food, is an anomaly for which we can offer no explanation, but 

 one which, from its interest, courts early investigation. 



The stomach of the kangaroo resembles the human colon and 

 caecum; the oesophagus enters near its left extremity, which is 

 small and bifid; the stomach first extends towards the right side, 

 and then upwards and to the left, in such a manner as to completely 

 encircle the entrance of the oesophagus, and terminates at the py- 

 lorus by a contracted orifice. Its cavity gradually enlarges from the 

 left extremity till it nearly reaches the pylorus, it then dilates into a 

 round cavity with two lateral processes, and finally ends by a 

 narrow orifice. It presents a sacculated appearance arising from 

 the presence of anterior and posterior bands like those of the human 

 colon, and the cuticle lines it to a certain extent on either side of 

 the entrance of the oesophagus. This animal has been known to 

 ruminate when fed on hard ifood. The kangaroO-rat and the vam- 

 pyre bat present similar modifications of stomach but have no part 

 of it lined with cuticle, and in the former there is a valve at the 

 cardiac orifice. The intestine of the kangaroo corresponds in its 

 great length and convolutions with the coarse nature of its vegetable 

 food, and the coecum is about fifteen inches long. At the cardiac 

 orifice of the stomach in the beaver and wombat there is a large 

 gastric gland, like the glandular infundibulum in birds. 



The ruminating animals possess four stomachs ; the first magnus 

 venter, or paunch, receives the crude unrnasticated food, while the 

 animal is grazing. When this cavity is filled the animal retires to 

 rest, and begins to ruminate; the unmasticated food, softened in 

 the paunch, now passes in small portions into the second cavity, 

 called reticulum, or honey comb ; from this it passes as a bolus up 

 through the oesophagus to the mouth, where it is thoroughly mas- 

 ticated and insalivated ; it is next couducted by the oesophagus to 



