OrperR UNGULATA. 
HOOFED MAMMALS. 
This order comprises the Hoofed Mammals, such as Deer, Oxen, 
Horses, Sheep, Swine, Elephants, etc.,* representatives of the various 
families being widely distributed throughout the world, except in 
Australia and Madagascar. They are terrestrial, digitigrade, and vege- 
tarian. The molars are broad, with ridged or tuberculate surfaces; 
the teeth are heterodont or diphyodont; and the “milk teeth” remain 
longer than in most mammals; clavicles are not present in living 
species; the digits vary from one to five, and are usually incased in a 
horny hoof, although in some cases, such as the Elephants, there are 
_broad blunt nails. 
The American Ungulates belong to two suborders: Perissodactyla, 
those having an uneven number of toes, such as the Horse and Tapir; 
and Artiodactyla, those possessing an even number of toes, such as 
Deer, Oxen, Sheep, etc. The latter are characterized by the prom- 
inence of the third and fourth digits, while the second and fifth are 
indicated by small lateral hoofs, or “false hoofs,’’ which are rarely, if 
ever, functional, and in some’ species are entirely absent. 
The suborder Artiodactyla is generally divided into two groups or 
divisions consisting of (1) the Suinea, comprising the families contain- 
of ing the Swine and Hippopottami; 
and (2) the Selenodontia, or Rum- 
) inantia,t comprising the other rep- 
“4N') resentatives of the suborder, such as 
Deer, Oxen, Sheep, etc., which rum- 
inate or “chew their cud.” 
In all ‘‘ruminants” the stomach 
Stomach of Ruminant. is usually divided into four com- 
o, Csophagus; b, rumen or pouch; h, reticu- 
lum or honeycomb bag; d, psalterium or manyplies; j ; 
c, abomasum or reed; f, duodenum. (After partments Gin the Tragulide there 
Flower and Lydekker.) are but three), and the operation 
consists of forcing back the hastily and improperly chewed grass or 
vegetable matter from the stomach into the mouth, where the food is 
* See page 28. 
+ The Ruminantia are again subdivided into somewhat natural groups: (1) 
Tragulina, comprising the Chevrotains or Deerlets; (2) Tylopoda, Camels, Llamas, 
Vicufias, etc.; and (3) Pecora, including the families Cervide, Deer, etc.; Girafide, 
Giraffes and Okapi; and Bovide, Oxen, Sheep, Goats, Old World Antelopes and not 
unlikely the American Antelope or Pronghorn, although the last is usually placed 
in a family by itself (A ntilocaprida). 
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