EVEN-TOED UNGULATES. 



697 



and restricted to the males in almost all Cervidse. There are no 

 upper incisors, and rarely upper canines ; there are three pairs of 

 lower incisors which bite against the hardened gum above, and 

 the lower canine resembles and is in the same series as the 



. . °°33 



incisors ; the typical dentition is . The stomach has four 



3133 

 distinct compartments, a psalterium or many-plies in addition to 

 the three which are present in Camels and Chevrotains. The 

 placenta is cotyledonary, the villi occurring on a number of 

 distinct patches. 

 The process of rumination or chewing the cud cannot be understood 

 without considering the complex stomach. It is divided into four 

 chambers, the paunch or rumen, the honeycomb bag or reticulum, the 

 many-plies or psalterium, the reed or abo- 

 masum. The swallowed food passes into 

 the capacious paunch, the walls of which 

 are beset with close set villi resembling 

 velvet pile. After the food has been 

 softened in the paunch, it is regurgitated 

 into the mouth where it is chewed over 

 again and mi.xed with more saliva. Swal- 

 lowed a second time the food passes not 

 into the paunch, but along a muscular 

 groove on the upper wall of the globular 

 honeycomb bag into the third chamber or 

 many-plies. The honeycomb bag owes its 

 name to the hexagonal pattern formed by 

 the mucous membrane on its walls. The 

 many-plies or psalterium is a filter, its 

 lining membrane being raised into numer- 

 ous leaf-like folds covered with papillse. 

 Along these the food passes to the reed, 

 which secretes the gastric juice. 



Cervida; — the widely distributed deer, 

 absent only from the Ethiopian and 

 Australian regions. The second 

 and fifth digits are usually repre- 

 sented, often along with the distal 

 parts of the corresponding meta- 

 carpals and metatarsals. The upper 

 canines are usually present in both 

 sexes. The horns, if present, are 

 antlers, confined to the males and 

 deciduous, except in the reindeer, 

 where they are possessed by both 

 sexes and are permanent. The}' 

 are outgrowths ol the frontal bones, 

 are covered during growth by vascular skin — the velvet — and 

 attain each year to a certain limit of growth. After the breeding 

 season the blood supply ceases, the velvet dies off, and an 



Fig. 253. — Side view 

 of Calf's fore leg. 



/;., Distal end of humeru.s ; 

 «., olecranon process of ulna ; 

 r., radius; mc^-^, metacar- 

 pals 3 and 4 fused to form 

 cannon bone ; ^iic.^^ fifth 

 metcarpal ; w., nodule. 



