THE TYLOPODA. 385 



bony substance beneatli is exposed. Absorption and 

 sloiigliing next occur at the extremity of the ^pedicel, jiist 

 as migbt happen in any other case of necrosis. The beam 

 and buiT are shed, and the end of the pedicel scabbing 

 over, fresh integument gradually grows up under the scab, 

 and eventually restores to the extremity of the pedicel its 

 pristine smooth and hairy covering. 



The rapidity with which the development of bony matter 

 into Deer horn takes place is wonderful, horns weighing 

 72 lbs. having been prodiiced in ten weeks. 



The Cohjloplwra are represented in all parts of the world 

 except the Australian and Novo-Zelanian provinces. They 

 have not yet been traced back further than the miocene 

 epoch. 



c. The CamelidtB or {Tylopoda) are devoid of horns; and, 

 unlike the other Ruminants, they walk upon the palmar 

 and plantar surfaces of the phalanges of the third and 

 fourth toes, which are alone developed. Broad integu- 

 mentary cushions form a sole to the foot ; while the nails 

 are flattened and can hardly be called hoofs. 



The arches of the cervical vertebrae, and not theii' trans- 

 verse processes, are perforated by the canal of the vertebral 

 artery; a character which the camels share with the 

 Macrauchenidce. 



The metacarpals are separated by a deep cleft, and the 

 distal phalanges of the digits are nearly symmetrical in 

 themselves. The distal facets of the astragalus are more 

 unequal than in the other Buminantia, and the navicular 

 and cuboid bones are not ankylosed together. 



The premaxillas have a single strong outer incisor on 

 each side. Large curved and pointed canines are developed 

 in each jaw, and are quite distinct from the series of the 

 incisors in the mandible. There are not more than five 

 grinding teeth in a continuous series above and below. 



The stomach is iinlike that of the typical Ruminants. 

 The oesophagus opens directly into the paunch, which is 

 lined by a smooth, not papillose, epithelial coat. From its 

 walls, at least two sets of diverticula, with comparativeh' 



2 c 



