xix.] UNGULATA. 321 



In the Tylopoda the cuboid and navicular are distinct. 

 There is no internal cuneiform. The second and fifth digits 

 are entirely absent. The metatarsals of the third and 

 fourth are united except * at their lower extremity. The 

 phalanges resemble those of the fore-foot. 



In the Tragidma the cuboid, navicular, and two outer 

 cuneiforms are united to form a single bone. The third and 

 fourth metatarsals are confluent. The second and fifth are 

 complete, extending from the small digits up to the tarsus, 

 but are very slender. 



In all the Pecora (Fig. 121) the cuboid (cb) and navicular 



(n) are united, as are the second and third cuneiform bones, 



and in some T>ttr(Cervulus and Pudu) these latter are farther 



united with the cubo-navicular ; the first cuneiform is always 



distinct, though small. 1 The third and fourth metatarsals 



(m in. and m iv.) are united in the same manner as the 



letacarpals, and the phalanges of the digits are very similar 



to those of the manus. The second and fifth metatarsals are 



ilways wanting ; the bones of the corresponding digits are 



ibsent in the Giraffe and most of the Oxen, Sheep, and 



Antelopes. In the Deer there are usually three small 



phalanges to each of these digits, not directly articulated 



with the rest of the skeleton. A large, oval sesamoid is 



commonly present in the plantar surface of the tarsus. 



The pes of the Hyrax closely resembles that of the 

 Rhinoceros, but the ungual phalanx of the second digit is 

 cleft almost to its base. 



In the Proboscidea the pes is short and broad, but 

 smaller and more compressed than the manus, and in the 

 more rudimentary condition of the two lateral digits shows 

 a greater tendency to approach the Perissodactyle form. 



1 See Sir Victor Brooke, Proceedings of the Zoological Society, 1874, 

 P- 34- 



Y 



