Ungulates 



M 



peculiar four-parted stomach and the habit of casting up the 

 hastily cropped grass for further mastication when resting later 

 on. This operation is called "chewing the cud," and one of the 



compartments of the stomach serves as 

 a receptacle for the food, while it awaits 

 this supplementary chewing. The canine 

 teeth are often wanting in the hoofed 

 animals and in the ruminant group the 

 front teeth or incisors of the upper jaw 

 are also lacking. The large grinders or 

 molar teeth are always present and exhibit 

 the most complicated type of tooth known. 

 Most of the ruminants are further peculiar 

 in the possession of horns or bony ant- 

 lers growing out from the top of the 

 skull. 



Great numbers of fossil ungulates 

 have been discovered and it has been 

 possible to show the gradual evolution 

 of the living species through a long 

 series of extinct ancestors. 



Remains of extinct horses and rhi- 

 noceroses have been found abundantly 

 within the United States as well as animals for which we have 

 no familiar names. To-day, however, our native ungulates are 

 comparatively few in number and are grouped in four families, 

 all of them belonging to the even-toed division. 



Foot of a ruminant (sheep) 



A Ankle bones. 



M Metatarsals fused together. 



S "Splints" or remnants of 

 other metatarsals. The corres- 

 ponding toe bones are seen below. 

 (After Lydekker) . 



I. Peccaries (Family Dicotylidce). Pig-like animals, not ruminant 

 and without horns. Canine teeth large and prominent, 

 front teeth (incisors) in both jaws. 

 II. Deer, elk, etc. (Family Cervidce). Ruminant animals with 

 bony branching antlers on the head of the males (and 

 females also in the caribou), which are shed every year. 

 Rudimentary canines generally present but front teeth 

 (incisors) only in the lower jaw. 



III. Prong horn (Family Antilocapridce) . Allied to the cattle 



(Bovidce), but the hollow horns are forked and are shed 

 as in the deer. 



IV. Cattle and their allies (Family Bovida). Ruminant animals 



with hollow horns fitting over bony prominences on 

 the skull in both males and females. These horns are 



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