MR. W. H. FLOWER ON THE OSTEOLOGY OF THE SPERM-WHALE. 339 



edge, for the seventh rib, is raised upon a small tubercle ; while the posterior surface, 

 for the eighth rib, is still further reduced and fiat. In the eighth (fig. 5) the anterior 

 facet is still more raised, and the posterior is nearly obsolete. In the ninth (fig. G) tlie 

 articular surface on the anterior edge of the body is developed into a distinct process, 2" 

 in length, springing from the anterior half of the side of the body, obliquely truncated, 

 and having on its outer and anterior surface an oval excavated articular facet, which 

 bears the head of the ninth rib. There is no trace of any articular surface on the pos- 

 terior edge for the tenth rib. In the tenth vertebra (fig. 7) the above-described tubercle, 

 developed from the anterior articular facet, takes the shape of a long massive process, 

 6" in length and nearly as much in antero-posterior thickness, springing from tlie 

 middle of the side of the body, slightly ascending, compressed from above downwards, 

 more expanded at the end than the middle, ending in a large, oval, concave articular 

 facet for the tenth rib, and having at its upper surface, near the extremity, a sub- 

 conical, compressed (from before backwards) process, which rises to meet the small 

 subcylindrical upper transverse process, approaching so closely on the right side as to 

 be separated by scarcely a line's breadth. The eleventh vertebra (fig. 8) has no articular 

 facets on the side of the centrum ; but the process arising from this part on a level with 

 that of the last-described vertebra, is still longer and more compressed, in fact precisely 

 resembling in situation and general character those found on the lumbar vertebrae, but 

 having at its extremity a small rough articular surface for the attachment of the 

 rudimentary eleventh rib. 



In the Caithness and Yorkshire skeletons the same essential characters are found, 

 differing only in details arising chiefly from more advanced age. In the Yorkshire speci- 

 men, in the ninth dorsal vertebra, the inferior process is so far developed as to meet the 

 upper one, forming a complete ring of bone on both sides. In the Caithness Whale this 

 ring is complete only on one side in the ninth, but on both sides in the tenth vertebra. 



In all known Cetacea (with the few exceptions to be presently mentioned) the 

 transverse process which arises in the fore part of the dorsal region from the side of 

 the neural arch, and is evidently serially homologous with tlie upper transverse pro- 

 cess [diapophjsis) of the cervical vertebrae, falls gradually and almost insensibly in 

 its pomt of origin from the vertebra, until, leaving the arch, it comes to be placed upon 

 the body of the vertebra, and is perfectly continuous serially with the transverse pro- 

 cesses of the lumbar vertebrae, which, from their situation, would be taken to represent 

 the inferior processes [parapopJnjses) of the cervical region. We find, moreover, after 

 leaving the region of the neck, no trace of two lateral processes on the same vertebra. 



The remarkable peculiarity of the Cachalot's spinal column is, that, tracing the upper 

 transverse process backwards from the neck, it never descends from its original position 

 on the arch, but, after a great reduction in importance, it completely disappears in the 

 eleventh vertebra ; while, on the other liand, a new process, springing from the side of the 

 centrum of the eighth or ninth vertebra, and being at first only a development of tlie 



