Mil 



PHYLUM CHORDATA 



543 



the Ruminant Artiodactyles (Fig. 11G2) the metacarpals or meta- 

 tarsals of these digits unite to form a single elongated bone, the 

 cannon hone. 



The pelvis of most Ungulata is greatly elongated. The ilia are 

 wide transversely, the symphysis is very long, involving a part of 

 the ischia as well as the pubes. In the PerissodacLyla, but not in 

 the Artiodactyla, there is a well-marked third trochanter. 



In some Ungulates (Rhinoceroses, Tapirs, Pigs, Hippopotami), the 

 fibula is distinct, though slender. In the Horse it is represented 



Dijzr 



Fiii. 111)3. — Dorsal surfiicu of 

 right tarsus of XXorse {Equus 

 caha/laa). n. astragalus ; c. cal- 

 caneum ; cb. cuboid ; c''. united 

 nicso- and ento-cuneiform ; A 

 ecto-cuneiform ; n. navicular ; 

 s. scaphoid ; ml/, IV, vestigial 

 second and fourth metatarsals; 

 ///, third metatarsal. (After 

 Flower.) 



■ mJa: 



Via. 1104. — Dorsal surface 

 of right tarsus of Red 

 Seer {Cervus elajihus). 

 a. astragalus ; c. cal- 

 eaneum ; cb. cuboid ; c'-K 

 conjoined ecto- and 

 meso-cuneiform ; uiIII, 

 iiiIV, third and fourth 

 metatarsals ; n. navi- 

 cular. (After Flower. ) 



Fig. 11(35.— Dorsal surface 

 of right tarsus of Pig 

 {Sv.s scvofa). a. astra- 

 galus ; c. calcaueuni ; 

 d>. cuboid ; e's. ecto- 

 cuneiform ; c-. meso- 

 cuneiform ; //(//— V. 

 metatarsals ; n. navi- 

 cular. (After Flower.) 



by a vestige. In the Ruminants it is represented only by a small 

 vestige, the malleolar hone, which articulates with the distal end 

 of the tibia. 



The structure of the foot exhibits a close parallelism to that of 

 the mauus. The tarsal bones are closelv dove-tailed together, 

 and articulate with one another by flat surfaces. The hallu.K is 

 never developed. In the Perissodactyla the third digit is sym- 

 metrical in itself. In the Rhinoceros and Tapirs the second and 

 fourth digits are also completely developed ; but in the Horses 

 (Fig. 1163; they are represented only by splint-like vestiges of 

 their metatarsals, the metatarsal of the third digit formino- an 



L L 2 



