354 



THE VERTEBRATE SKELETON. 



be completely wanting. The lumbar and caudal vertebrae are 

 large and numerous, and as zygapophyses are absent, are very 



FIG. 67. 



--3 



CERVICAL VERTEBRAE OP A CA'ING WHALE (Globicephalus 

 melas) x . (Camb. Mus.) 



1. centrum of seventh cervical 



vertebra. 



2. neural arch of seventh cer- 



vical vertebra. 



3. transverse process of atlas. 



foramen for exit of first spinal 



nerve. 



transverse process of axis, 

 fused neural spines of atlas 



and axis. 



freely movable on one another ; zygapophyses are also absent 

 from the posterior thoracic vertebrae. The lumbar vertebrae 

 are sometimes more numerous than the thoracic. The epi- 

 physes are very distinct, and do not unite with the centra till 

 the animal is quite adult. None of the vertebrae are united 

 to form a sacrum, but the caudal vertebrae have large chevron 

 bones. 



The skull is peculiarly modified; the bones forming the 

 occipital segment show a specially strong development, and 

 the cranial cavity is short, high, and almost spherical. The 

 supra-occipital is very large and rises up to meet the frontals, 



