40 CERVICAL VERTEBRAE [chap. 



and as ossification takes place gradually from within out- 

 wards, and does not reach the outer extremity until the 

 animal approaches maturity, specimens are frequently met 

 with in museums, which, instead of completely annular 

 transverse processes, show only truncated upper and lower 

 bars. In some species, however (as in Megaptera longiinatia)^ 

 most of the cervical vertebrae remain permanently in this 

 condition. 



Among the Odontoceti, all the cervical vertebrae are free in 

 the Gangetic Dolphin {Flafa/iisia), and in the allied South 

 American genera Inia and Pontoporia, also in the Nar- 

 whal i^Monodon) and the Beluga, or the White Whale. In 

 most of these genera the atlas has a large hypapophysial 

 process, projecting under and articulating with the body of 

 the axis, which develops no distinct odontoid. In the 

 Narwhal irregular ankyloses between the bodies of the cervical 

 vertebrae are very frequent. In all the other Delphinidce 

 (including Delphiims, Orca, Pseudorca, Globicephalus, Pho- 

 ccBua, &c.), at least the first and second cervical vertebrae 

 are united by both body and spine, and most commonly 

 some of the succeeding vertebras are joined to them. If 

 any are free, it is always those situated most posteriorly, 

 and they have extremely thin, sub-circular disk-like bodies, 

 and irregular and comparatively rudimentary transverse 

 processes. 



In Hypcroodon^ the whole of the cervical vertebrae are 

 ankylosed together. In the other Ziphioids several of the 

 posterior vertebrae are free, and the allied Cachalot, or Sperm 

 Whale {Physcfer), presents a condition not met with in any 

 other known Cetacean : the atlas is free, and all the other 

 neck vertebrae are completely united. 



Among the various members of the order Edentata, the 

 cervical vertebrae present very different conditions. 



