Z CATALOGUE OF UNGULATES 



same complex type as the molars (fig. 3, p. 5), and the last 

 lower molar commonly carries only two lobes, or, if it has 

 three, the hindmost is not developed in the corresponding tooth 

 of the premolar series. The femur carries a large, curved 

 "third trochanter" for the insertion of one of the gluteal 

 muscles. In the tarsus the upper surface of the astragalus 

 is pulley -like, for articulation with deep grooves in the lower 

 end of the tibia, but its lower aspect (unlike that of the 



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IV 



FIG. 1. BONES OF THE LEFT FORE-FOOT OF A HORSE (A) 

 AND OF A RHINOCEROS (B). 



.r, radius; u, ulna; c, carpus (forming the so-called "knee" of the 

 Horse) ; me, metacarpus (constituting the " cannon-bone " in the 

 Horse); ph, phalanges, or toe-bones. II, III, IV, the toes corre- 

 sponding to those so numbered in the typical series of five, the lateral 

 metacarpals being represented in A by the "splint-bones" at the 

 tipper end of the median metacarpal. 



Artiodactyla) is flattened, and articulates to a much greater 

 extent with the navicular than with the cuboid, which is 

 less developed than in the even-toed group. The stomach is 

 simple, and the caecum large and capacious. The placenta 

 is diffuse and devoid of cotyledons ; the teats are invariably 

 inguinal in position ; and the liver lacks a gall-bladder. 

 When cranial appendages are present they are quite different 

 in structure from those of the Artiodactyla. 



