536 



IIE. W. H. FLOWER ON THE OSTEOLOGY OF THE SPERM- WHALE. 



The spinous processes progressively increase in height from before backwards. That 

 of the first is a small ii-regular tubercle broader than long, and scarcely higher than that 

 of the conjoined cervical vertebrae. That of the second is still inconspicuous, but more 

 compressed from side to side. The great antero-posterior width characteristic of the 

 remainder begins to be seen in the third. The spines of the fifth, sixth, and seventh 



Anterior surface of the fourth dorsal vertebra and head of right rib. 



scai'cely differ in form and dimensions, being, when seen from the side, nearly square. 

 From the eighth a more rapid increase in vertical height takes place, until the last, 

 by its elevation, narrowness at the base, and expansion at the extremity in the antero- 

 posterior direction, as well as in thickness, resembles that of one of the lumbar vertebrae. 

 As far as the sixth theii- general direction is vertical ; afterwards they have a slight but 

 gi-adually increasmg backward slope. 



Well developed rough processes, which can hardly be called articular surfaces, but 

 representing the posterior zygapophyses, are formed on the hinder edge of the sides of 

 the neural arch, at the root of the spine, from the fii-st to the ninth vertebra inclusive. 

 In the tenth they have almost lost their distinctive character, and they are quite obsolete 

 in the eleventh. They lie above and within the prozygapophyses of the succeeding ver- 

 tebra ; but, except in the case of the first two or three, they appear very rudely coadjusted, 

 compared with those of orduiary Mammalia. 



The prozygapophyses are at first represented by a flattened surface on the angle 

 formed by the junction of the pedicle, lamina, and transverse process of the vertebra (to 

 use the familiar terms of anthropotomy), or at the root of the diapophysis. Gradually 

 this part increases in prominence, and forms a distinct rounded eminence, projecting 

 upwards and forwards from the side of the neural arch, and bearing the smooth 

 articular surface (distinct as far as the tenth vertebra), to its inner side. The sudden 

 diminution of the diapophysis on the tenth vertebra, and its disappearance on the 

 eleventh (see figs. 7 and 8), leaves this, though somewhat contracted in bulk, a con- 



