41G ORGANS OF DIGESTION. 



garoo, and corresponding, as in these, with the inferior 

 quality of the food. 



The typical forms and characters of the human digestive 

 apparatus (130. E.) are gradually developed and established in 

 the diversified order of quadrumanous animals. The cheek- 

 pouches, so frequent in the inferior mammalia, and so general 

 in the simiae of the old continent, and which are mere exten- 

 sions of the thin parietes of the mouth outwards and backwards 

 over the ramus of the lower jaw, covered and moved by nume- 

 rous fasciculi from the pJatysma myoides and the buccinator 

 muscle, are already lost in the orangs as in man ; the rounded 

 tubercles of the molar teeth, common to the higher quadru- 

 mana and man, accord with the softer condition of the food 

 natural to these two tribes, and the uvula and velum palati 

 are most developed in our species. The muciparous labial 

 and buccal glands, which soften the contents of the cheek- 

 pouches, are more constant and larger in man ; but the 

 parotid, sub maxillary, and sublingual salivary glands, ap- 

 pear to exceed the human in the more frugivorous forms 

 of quadrumana. The shortness of the oesophagus (130. E. 

 a.) corresponds with that of the neck, and the elevated posi- 

 tion of the head, in the quadrumana and man ; its muscular 

 fibres form an inner transverse and an exterior longitudinal 

 layer, in place of the opposed spiral fasciculi of inferior 

 mammalia ; ana it enters the stomach (130. E. b.) at the 

 shortest distance beyond the pillars of the diaphragm. The 

 stomach is less elongated transversely, and less generally 

 constricted in the middle, in the quadrumana, than in man, 

 but the cardiac coecum is most developed in the former, and 

 especially in the lowest tribes, where also the most length- 

 ened form of the mesentery suspends the convolutions of the 

 intestine. The human valvube conniventes are still wanting 

 in the duodenum ; but the glandule Peyeri are often much 

 more numerous, and more extensively spread over the intes- 

 tine, than in man, where they are confined to the lower part 

 of the jejunum and ilium. The duodenum (130. E. c.) re- 

 ceives the secretions of the liver (130. E. /. /.) and pancreas 

 (130. E. h.) by a single orifice of the united ducts, in the 

 simise, as in man. The gall-bladder (130. E. m.) is always 

 present, the liver is more deeply lobated in the lower qua- 

 drumana, and the spleen (130. E. i.) has generally a more 



