Mk. W. H. FLOWER ON THE OSTEOLOGY OF THE SPERM-WHALE. 345 
‘The neural arch forms a distinct canal as far as the fifteenth caudal vertebra; in the 
sixteenth and following vertebre the processes which represent it do not meet across 
the middle line. In the Caithness Cachalot the canal terminates at the eleventh caudal, 
in the Yorkshire specimen at the twelfth. In the anterior vertebra (with elongated 
bodies) the neural lamin arise from little more than the anterior half of the body, but 
posteriorly, as the bodies decrease and the lamine actually increase in the antero- 
posterior direction, they come to occupy nearly the whole length of the upper surface 
of the centrum. This is best seen in the ninth and tenth. In the first caudal vertebra 
the metapophyses form prominent flattened wing-like processes, projecting forwards 
and outwards from the front border of the neural spine, having a deep groove between 
them for the reception of the hinder edge of the spine of the last lumbar vertebra. 
‘Their upper and anterior edges are thickened, rough, and slightly everted. They are 
placed about halfway between the upper surface of the centrum and the highest part 
of the spine. In the five following vertebre their height from the centrum remains 
almost precisely the same; but the spine gradually diminishes, so that in the sixth 
its upper edge comes to be on a level with these processes; at the same time they 
alter in character, becoming shorter and thicker, and terminating in a nearly cir- 
cular, flat, but very tuberculated or rugged surface, looking upwards and forwards ; 
after the third they are so truncated and placed so near together upon the anterior 
thickened edge of the neural spine, as to have scarcely any groove between them, 
and to have quite lost the “clasping” character they exhibit in the lumbar region. 
In the seventh caudal vertebra they have disappeared altogether, in consequence of 
the diminution of the height of the spine, or are only slightly indicated in the laterally 
thickened anterior extremity of the spinous process. Thereafter the spinous processes 
are of a very simple nature, compressed from side to side, elongated from before back- 
wards, and truncated above. The eleventh is less compressed; the twelfth of quite 
another form, broad and flat above, the sides meeting at a very open angle; the thir- 
teenth a mere irregular low tuberosity, perforated by a small canal 38;” high by 34,” 
wide. In the fourteenth and fifteenth the canal is much smaller in front than behind: 
in the last it is not so large as a goose-quill, and bridged over only for the space of 
half an inch. In the remaining vertebre the upper surface of the bone has four 
tubercles, arranged in pairs—two near the front and two near the hinder edge, the 
anterior pair being the largest. Traces of these can be discovered as far as the penul- 
timate vertebra. 
In the anterior vertebree of the series the transverse processes project outwards 
with an inclination slightly downwards and forwards, from rather below the middle 
of the side of the body. ‘They soon diminish in length, and increase in width from 
before backwards. In the ninth vertebra they are reduced to roughened longitudinal 
ridges; in the tenth they have entirely disappeared, and their place is taken by a 
slight groove. In the Caithness Cachalot the transverse process is rudimentary in the 
3B2 
