410 



ANATOMY OF VERTEBKATES. 



308 



Pure saliva obtained from the parotids and submaxillaries of a 

 dog, and from the parotids of a horse, is incompetent to effect the 

 saccharine transformation of starch : but the secretion of the 

 mucous and subsidiary glands of the mouth reacts upon either 

 starch or sugar in the way of producing lactic acid. 



§ 225. Alimentary canal, Lyencephala. — In the Ornitho- 

 rhynchus the oesophagus becomes slightly dilated near the dia- 

 phragm, extends a little way into the abdomen, and expands into 



a moderate-sized membranous 

 stomach, fig. 308, t, which is 

 chiefly remarkable for the close 

 approximation of the cardiac and 

 pyloric orifices. The intestinal 

 canal is moderately wide, five feet 

 three inches and a half in length, 

 and provided, at a distance of 

 four feet three inches from the 

 pylorus, with a small and slen- 

 der cascum, ib. w. The small 

 intestines are chiefly remarkable 

 for the extent of the mucous 

 coat, which is disposed in nume- 

 rous folds or valvular conniventes : 

 these are transverse at the be- 

 ginning of the duodenum, but are 

 placed more or less obliquely in 

 the rest of the small intestine ; 

 they are about two lines broad, 

 are close together in the duode- 

 num, but diminish in breadth 

 and number as they approach the 

 cascum coli. There are about 

 fifteen longitudinal folds in the 

 first half of the colon; the re- 

 mainder of the intestine has a 

 smooth inner surface. There is 

 no valvula coli. The rectum, 

 ib. z y terminates at the anterior 

 and dorsal part of the vestibular 

 compartment of the cloaca. 



As the food undergoes less 

 comminution in the mouth of the Echidna than in that of the 

 Ornithorhynchus, the pharynx and oesophagus are wider, and a 



Thoracic and abdominal viscera, Ornithorhynchus, 



LXXXl'. 



