MR. W. H. FLOWER ON THE OSTEOLOGY OF THE SPERM-WHALE, 347 
middle by these grooves on each side below, and by the one connecting the two fora- 
mina (here much reduced in diameter) on the upper surface, that at first sight it looks 
like two vertebree which have coalesced, as not unfrequently occurs in this region among 
true Whales. The last vertebra is a rough, broad, oval nodule of bone, truncated in 
front, obtusely pointed behind, flattened from above downwards. ‘Traces of the vascular 
‘ grooves are to be detected on its sides. The contiguous surfaces of this and the penul- 
timate are both concave; but the irregularities of their prominent edges correspond 
exactly, and they have evidently been in close apposition. 
The last twelve vertebre of the tail of another Cachalot, sent to the Museum by 
Mr. Crowther in 1866, resemble those of the skeleton in their general characters, 
and evidently correspond vertebra for vertebra, but with considerable individual de- 
viations. They are, in the first place, all rather shorter in proportion to their breadth. 
The entire length of the twelve placed in apposition is 38”, while the twelve cor- 
responding vertebre of the skeleton measure 42”, the breadth of the former slightly 
exceeding that of the latter. The neural arch is not completely closed in by bone 
even in the first of the series. The penultimate is much shorter than that of the 
specimen described above. The terminal vertebra is altogether smaller, and does not 
present the broad, depressed character of the other, but is a simple rough subconical 
nodule. ‘The first of the set had a perfect chevron bone attached to its hinder edge, 
5” in greatest depth, and 4’ in length. The second had another, consisting of two 
distinct oval plates 22” deep by 23” long. There were no further traces of hema- 
pophyses, which, from the state of the specimen, must have been preserved if they had 
ever existed. 
The Tasmanian, Sydney *, Caithness, and Yorkshire Cachalots resemble each other in 
possessing a distinct atlas, followed by six ankylosed cervical, and ten dorsal vertebree 
bearing well-developed ribs. They agree, moreover, in possessing eight true lumbar 
vertebre. The Sydney specimen, however, according to the published description, wants 
the vertebra intermediate between the dorsal and the lumbar series, found in the other 
three, and hence has one vertebra less in front of the first chevron bone. Of remain- 
ing or caudal vertebre, the Tasmanian and Sydney specimens have twenty-four, the 
Yorkshire specimen (presuming it to be complete) twenty-three, while in the Caith- 
ness one the number cannot be stated with certainty. The Yorkshire and Sydney 
Cachalots, therefore, agree in the entire number of vertebre being forty-nine, while 
the Tasmanian skeleton possesses fifty. These differences are so trifling that they 
may be the result of accident or individual peculiarity; they certainly by them- 
selves afford no assistance in discriminating between a northern and southern species of 
the genus. 
Nor do we find, on reverting to the special characters of the vertebrae, any more 
* Wall, op, cit. 
