IV.] UNGULATA. 35 



have large inferior lamelke. That of the seventh is usually 

 imperforate. 



In the Giraffe the bodies of the cervical vertebrae are very 

 long. The transverse processes are short, but so extended 

 from before backwards as to become divided into two, one 

 at the anterior and one at the posterior end of the vertebra. 

 That of the seventh is perforated. 



In the Tylopoda (Camels and Llamas) the vertebrarterial 

 canal passes obliquely through the anterior part of the 

 pedicle of the arch, being in its posterior half confluent with 

 the neural canal. A similar condition occurs in Alacrau- 

 cheuia, an extinct South American Perissodactyle Ungulate. 



The Siii/hi and Tragidina differ from the remaining exist- 

 ing Artiodactyles in the form of the odontoid process, which 

 is conical ; while on the other hand the Horse and Tapir 

 among the Perissodactyles have this process wide, flat, and 

 hollowed above, approaching the form it presents in the 

 Ruminants. In the Pig, the broad pedicles. of all the cervical 

 vertebrae are perforated by canals for the passage of the 

 upper division of the spinal nerves. 



The bodies of the cervical vertebrae in the Rhinoceros, 

 Tapir, and Horse are markedly opisthocoelous, but in the 

 Pig and Hippopotamus very slightly so. 



In the Horse the bodies of the cervical vertebrae are 

 elongated, with a strong keel and hypapophysial spines. 

 The neural laminae are very broad, the spines almost obso- 

 lete, except in the seventh, and the transverse processes not 

 largely developed. The seventh is not perforated by the 

 vertebrarterial canal. 



In the Rhinoceros, on the other hand, the bodies are 

 comparatively short, and not keeled, the laminae narrow, the 

 spines well marked, and the transverse processes greatly 

 developed, especially those of the atlas. 



D 2 



