MR. W. H. FLOWER ON THE OSTEOLOGY OF THE SPERM-WHALE. 365 
firm this description. Iu addition to the single bone which accompanied the skeleton, 
Mr. Crowther has presented to the Museum two other pelvic bones, taken also from 
adult male animals; but neither of them bears traces of any original segmentation. 
They all present the general characters common to the corresponding bones in other 
Toothed Whales, but have, as is so frequently the case, strongly marked individual 
peculiarities. They are all more or less compressed, slightly expanded at one end, 
which was tipped with cartilage, and present some modification of a sigmoid curve. 
The bone which belonged to the skeleton (see Pl. LX. figs. 5 and 6) is 14” long; at the 
middle its diameters are 1"°3 and 0-95; at the expanded end 2" and 1""1._ Its surface 
generally is simple and smooth; but at 4" trom the smaller end one of the margins rises 
into a triangular elevation surmounted by two short rough processes having different 
directions. 
Of the two other bones (which, though apparently belonging to opposite sides of the 
body, are stated to have been taken from different individuals), one (Pl. LX. fig. 7), 
though closely corresponding in actual length and thickness to the last, is so strongly 
curved that in a straight line its two extremities are but 12" apart. Its surface is more 
angular, presenting several strong longitudinal ridges and grooves. Near the middle of 
its greatest convexity is a small but prominent spine 0-4 in length; but otherwise there 
is no appearance of the lateral process so well marked in the last. Both ends were 
tipped with cartilage. 
The third bone (fig. 8) is the largest of the three. It is distinguished by a very 
regular sigmoid curve, by its smoothness, and the absence of all spine or process, and 
especially by- its great compression, and corresponding width in the opposite direction. 
Its length is 14""1, its diameters at the middle 2’-4 and 0-9, at the broader end 3'-7 
and 0''9, As in the first-described specimen, the more pointed extremity is smoothly 
rounded and evidently complete ; the condition of the other end shows that it had a 
cartilaginous continuation. 
The principal part played by these bones in the economy of the animal would 
prepare us to find that they presented considerable differences according to the sex of 
the individual to which they belonged ; but in those genera in which the entire magni- 
tude of the male and female differs but little, we do not generally find a very marked 
difference in the pelvic bones. Thus, in two perfectly adult Porpoises of nearly equal 
dimensions, the length of the pelvic bones of the male was 54", of the female 42*. In 
the Hunterian collection is a dried preparation of the penis of a Hyperoodon with the 
ischial bones still attached to the crura. The animal, from the size of these and other 
parts preserved in the Museum, as well as from a statement of Hunter, must have been 
much larger than the ordinary Hyperoodon rostratum, and probably belonged to the 
supposed species called /. latifrons, Gray, regarded by Eschricht as the adult male of 
* It appears, according to Eschricht’s observations, that in the genus Orca the pelyic bones show consi- 
derable sexual differences. (Recent Mem. on Cetacea, Ray Soc. 1866, p. 176.) 
VOL. VI.—PART VI. 3E 
