332 



MR. "W. H. FLOWER ON THE OSTEOLOGY OF THE SPERM-WHALE. 



The remaining six cervical vertebrae are completely soldered together, both by their 

 bodies and their neui-al spines, into one mass. Their individuality can be traced 

 distinctly enough at the root of the neural arches, where, for a short space, they are 

 separated to admit of the passage of the cervical nerves; but their conjoined spines 

 jjresent a solid mass in which no trace can be detected of separate vertebral elements ; 

 and their bodies are almost as completely fused together, slight grooves and rows of 

 foramina for blood-vessels on the lateral parts faintly indicating the limits of the several 

 component vertebrsE. The union of the seventh to the antecedent vertebrae is more 

 complete than in any other known Cetacean ; for even in the Hyperoodon the whole 

 of its neural arch is free. To this mass, in the Tasmanian specimen, the first dorsal 

 vertebra is partially united by its centrum only. 



The most remarkable characteristic of these vertebrae taken together is their extreme 

 antero-posterior compression, the four middle bones being most affected. The greatest 

 length, the lateral part of the conjoined bodies, is 9" ; and the whole group will lie between 

 two parallel planes no greater distance apart. The conjoined centrums are somewhat 

 flattened from above downwards, and very broad from side to side at the anterior end, 

 but less so posteriorly. 



Fig. 3. 



Anterior surface of second cervical vertebra. 



The anterior surface is, in the main, flat. Its median portion, 8" broad, is irregular, 

 rough, and slightly raised ; in the centre of this is a ridge-like prominence, placed with 

 its longest diameter vertically, and raised not more than f" above the surrounding 

 bone ; this represents the odontoid process. The lower edge is smoothly hollowed 

 out in the middle to receive the process on the contiguous portion of the atlas. 

 On each side of this hollow and of the median rough surface are the comparatively 

 smooth, slightly depressed, and nearly flat articular facets for the atlas, of an irre- 

 gularly quadrilateral figure, each measuring 10" in height, and 8" in width. Tliey 

 extend quite to the lower edge of the bone. Beyond these externally are the flat 

 anterior surfaces of the broad, obtusely pointed, transverse processes, projecting 5" from 



