348 MR. W. H. FLOWER ON THE OSTEOLOGY OF THE SPERM-WHALE. 
certain indications of difference. Each of the three vertebral columns which have 
passed under more immediate observation shows certain peculiarities; but what similar 
part of the organization of any given species of animal will not do sot And it must be 
remembered that, in these huge bones, differences of form and proportion are rendered 
most conspicuous which would almost escape observation in specimens of the size of 
those with which we are more accustomed to deal, and, further, that the ossification in 
the Sperm-Whale, more even than in other large Cetaceans, seems to have a special 
tendency to exuberant and irregular development, producing a great amount of indivi- 
dual character in the rugged masses composing the skeleton. 
It may be as well, however, to bring together the principal points of difference, such 
as they are, in the three skeletons. ‘The first to be mentioned relates to the length of 
the column when the vertebre are placed in close apposition. This is, in the Yorkshire 
one, 29’ 5”, in the Caithness one (allowing for the missing caudal vertebrae) 29! 3”, in the 
Tasmanian one 30! 4”. It must be remarked that the last, though the longest, is the 
least mature of the three animals. In the first two the correspondence is exceedingly 
close. With regard to the third, something must be probably allowed for the fact 
that the loose epiphyses of the ends of the vertebra, having become detached in 
maceration, could not be made to fit again so closely as they would if ankylosed; and 
hence the length of each vertebra was increased to a very slight extent. The differ- 
ences in the proportions of the individual vertebre are given in the Table at p. 327. 
They are not inconsiderable, but are as great in the case of the two British specimens 
as between either of these and the Tasmanian one. The greater height of the lumbar 
vertebra of the two former as compared with the latter, is chiefly due to the increased 
development of the keel of the body, apparently a consequence of superior age. Slight 
differences in the atlas, chiefly relating to the form of the lower part of the central 
opening, and to the development of the transverse processes, have been already spoken 
of in the description of that bone. 
In the annexed Table I have given the vertebral formula of the principal members 
of the group of Delphinoid Cetaceans, as far as I have been able to ascertain them from 
perfectly reliable sources. 
PHYSETERID. 
Physeter macrocephalus australis (Mus. Roy. Coll. Surg.), C. 7, D. 11, L. 8, C. 24=50. 
P. macrocephalus australis (Wall), C. 7, D. 10, L. 8, C. 24=49. 
P. macrocephalus borealis (Yorkshire), C. 7, D. 11, L. 8, C. 23=49. 
Kogia grayii (Wall), C. 7, D. 14, L. C. 30=51. 
Hyperoodon rostratum (Mus. Oxford and Vrolik), C. 7, D. 9, L. 10, C. 19=45. 
H. rostratum (Amsterdam and Roy. Coll. Surg.), C. 7, D. 9, L. 10, C. 18=44. 
Micropteron sowerbyense (Van Beneden), C. 7, D. 10, L. 10, C. 19=46. 
Ziphius cryptodon (Burmeister), C. 7, D. 10, L. 12, C. 20=49. 
