BALJ^INOPTERA. 



559 



Fig 22. 



that the epiphyses of the vertebrae are completely amalgamated with the body and 

 the spinous process, it shows no trace of having being capped with cartilage ; this 

 vertebra seems to have attained maturity, and, as in B. schlegeli, it has always the 

 two transverse processes widely apart. The seventh cervical has a nodular rudiment of 

 an inferior transverse process well-defined, and in this, this vertebra differs from the 

 corresponding vertebra of B. schlegeli. 



The spinous processes of the first two dorsal vertebrae correspond in character 



to the spinous processes of the cervical vertebrae, and in 

 the third and fourth dorsals, they partake more of the 

 characters of the cervical than of the dorsal vertebrae, 

 but, in the fifth, the process suddenly assumes the broad 

 expansion usual to a dorsal spinous process. The spinous 

 processes are antero-posteriorly broad, and of considerable 

 height (fig. 22), the maximum elevation being attained 

 not until the eighth lumbar is reached. There is a slight 

 anterior curvature of the spinous processes of the fourth 

 and fifth dorsals, but in the succeeding dorsal vertebrae 

 the backward direction of the processes become more and 

 more pronounced to the eighth lumbar, behind which the 

 processes gradually curve forwards and become more 

 erect. One of the distinguishing features of these pro- 

 cesses is the concavity of the anterior and posterior 

 margins, associated with the expansion of their free 

 ends and their considerable backward direction, which 

 confers on the vertebrae a very different character from that of the vertebrae of 

 B. schlegeli, as figured by Van Beneden and Gervais in their magnificent work on 

 the Cetacea. 



In the caudal region, the spinous process in the first is but little concave 



anteriorly ; still it has consid- 



Ninth dorsal vertebra, ^th natural size. 



risr. 23. 



Fig. 24. 



erable length. As measured 

 from its base anteriorly, it 

 exceeds the antero-posterior 

 length of the body of the 

 vertebra by nearly a half the 

 length of the latter. In the 

 second caudal it is much re- 

 duced in height, and in the 

 following vertebrae it so 

 rapidly dwindles away in size 

 that in the ninth it com- 

 pletely disappears. In the accompanying woodcuts (figs. 23 and 24) I give the 

 character of the caudals as seen in the sixth vertebra of the tail. 



' Ost^ographie des Oetaces, Livre ii., T. 14 et 16. 



Posterior view of the sixth caudal 

 vertebra, fth natural size. 



Upper aspect of the sixth caudal, 

 ith natural size. 



