Digestive System Special. 91 



Perissodactyla. In Ehinoceros the lining membrane of the Duo- 

 denum is, at the commencement, jpuckered up into irregular rugce ; 

 flattened triangular processes begin to make their appearance about 

 six inches from the pylorus ; in the Jejunum three or four of these 

 processes are often supported on a common base ; as they approach 

 the Ileum they begin to lose breadth and gain in length, until they 

 assume the appearance, near the end of the Ileum, of vermiform 

 processes, like tags of worsted, from two-thirds of an inch to one 

 inch in length. 



JByracoidea. The agminate follicles are lodged in fossae of the 

 mucous membrane. The small Intestines present internally a series 

 of twelve small pouches, which make no projection externally, being 

 situated wholly beneath the muscular coat. 



Artiodactyla. In many species of Euminantia, especially Giraifa, 

 the same arrangement of the Agminate Pollicles is observed as in 

 Hyracoidea. 



In-Enamellata. In Myrmecophaga the inner surface of the Duo- 

 denum and Jejunum is smooth, presenting no villi to the naked eye. 

 In Dasypus peba there is a well-marked zone of racemose glands 

 beyond the Pylorus, In Orycteropus the small Intestines are of 

 unwonted length, about thirty-seven feet, and their lining membrane 

 without folds, but beset with fine villi. 



MarsupiaUa. In most species, even the most carnivorous, there 

 is a zone of glands at the commencement of the Duodenum. In 

 Phascolarctos the end of the Ileum protrudes for the extent of a 

 quarter of an inch within the Caecum. 



Monotremata. The mucous coat of the Intestine of Ornithorhyn- 

 cus contrasts with that of Echidna in the presence of numerous 

 transverse and oblique folds, which are absent in the latter. 



16. The Cmcum 



is absent in 



most Insectiwra^ except the Tupaias and some snouted Shrews ; 

 all Cheiroptera^ except Rhinopoma and Megaderma Spasma ; 

 the Myoxidoi of the Eodentia, which hybernate, like the Bear ; 

 the Semiplantigrade and Plantigrade Sectorialia ; 

 and in the Bradypodidce (Inenamellata). 



is small and simple, though occasionally bifid, in 

 Bimana, where it is short, wide, and sacculated ; 

 the Catarrhine and Flatyrrhine Quadrumana ; 



