MAMMALS. 581 



the food in the first and second stomach is penetrated by alkaline 

 fluids, and only after having been ruminated does it imbibe in the 

 manyplies and the red an acid gastric juice. Thus it is here alone 

 that a true digestion, similar to that in the simple stomach of other 

 animals, is effected. 



The chyme, the product of stomachal digestion, passes into the 

 duodenum, the first part of the small intestine. The small intes- 

 tines are mostly longer than the large intestines, and on the inside 

 are beset with mill or elongated folds. Villi are commonly present, 

 in few instances only (as in the mole, the genus Chrysochloris, the 

 Ornithorliynchus, &c.) are they absent. At the union of the large 

 and small intestines there is usually found a ccecum; in one species 

 of ant-eater (Myrmecophaga didactyla) there are, as in birds, two 

 coeca at the entrance of the small intestine into the large ; in 

 Myrmecophaga jubata the coecum is absent. In Hyrax there is a 

 short and wide coecum in the usual position, whilst lower down 

 in the large intestine (colon) there are two other blind and conical 

 appendages placed side by side. It has been supposed that a second 

 digestion, a final separation of the nutritious matter of the chyme, 

 is effected in the ccecum, and in support of the opinion the resem- 

 blance between this part in some animals and the stomach in other 

 mammals has been adduced. The excrements, consisting of the 

 unaltered residue of the chyme, of bile, and mucus, are now formed 

 and gradually assume a greater consistence in the course of the 

 large intestines. The termination of the intestinal canal is usually 

 distinct from the sexual aperture, but in the duck-mole and in 

 Tachyglossus there is a cloaca as in birds. At the end of the 

 rectum glands are frequently situated which secrete a fatty and 

 strongly odorous fluid, as in the badger (Meles), the hyena, &c. 



The relative length of the intestinal canal is usually greater in 

 mammals than in the other classes of vertebrate animals, but differs, 

 however, in the different genera. In general the intestinal canal is 

 longest in the vegetable feeders; thus in the ox it is more than two 

 and twenty times the distance from the mouth to the anus, and in 

 a full-grown animal is one hundred and fifty feet long; in the 



coat, whilst their openings are on the inner surface of the stomach. Compare Bis- 

 CHOFP Ueber den Ban der MagenscJdeimhaut, MUELLER'S Archiv, 1838, s. 503525. 

 These folliculi secrete the gastric juice. 





