592 MR. Ww. H. FLOWER ON THE SKELETONS OF WHALES [Nov. 8, 
makes a fourth genus, Benedenia. Although I am as little disposed 
as any one to multiply generic names (a tendency of modern times 
of which we are all apt to complain), I cannot help admitting that, 
if the genera of Whales are to be at all equivalent in value to those 
now generally received in other groups of mammals, the first three 
of these are perfectly valid. Of the genus Benedenia I speak with 
more hesitation, as it is constituted only upon the examination of 
a very young individual, which I confess I am unable to distinguish 
from a Physalus. As the diagnostic characters given by Dr. Gray 
are brief, and limited to certain parts of the organization, I may be 
permitted perhaps to give more detailed characters taken from the 
skeleton generally, which will, I think, fully confirm his views as far 
as these genera are concerned. Into those characters, taken from 
the external form, position of dorsal fin, or from the visceral anatomy, 
it is not my purpose to enter at present. 
A. Physalus, Gray. Total number of vertebree 61-64. Ribs 
15 pairs*. Orbital process of frontal bone considerably narrowed 
at its outer end. Nasal bones short, broad, deeply hollowed on 
their superior surface and anterior border (fig. 4). Rami of the 
lower jaw massive, with a very considerable curve, and a high, pointed, 
curved coronoid process. Neural arches of the cervical vertebrze 
low ; spinous processes very slightly developed. Transverse process 
of the atlas arising from the upper half of the side of the body, long, 
tapering, conical, pointed directly outwards. Upper and lower trans- 
verse processes, from the second to the sixth vertebree, well deve- 
loped, broad, flat (and united at the ends in the adult, forming 
complete rings?). Head of the first rib simple, articulating with 
the transverse process of the first dorsal vertebra. Second, third, 
and sometimes the fourth ribs with capitular processes, reaching 
nearly to the bodies of the vertebrae. Sternum broader than long, 
in the form of a short broad cross, of which the posterior arm is very 
narrow ; it might perhaps be compared to the heraldic trefoil (fig. 7) ; 
it is subject, however, to considerable individual modifications. 
Type species, P. antiquorum, Gray. 
B. Sibbaldius, Gray, Total number of vertebrae 56-58. Ribs 
14 pairs. Orbital process of frontal bone nearly as broad at outer 
end as at the base. Nasal bones elongate, narrow, flat, or very 
slightly hollowed on the sides of the upper surface, obliquely trun- 
cated at the anterior end (fig. 5), Lachrymal bones thickened and 
rounded at the outer end. Lower jaw with a comparatively slight 
curve, and a low, obtusely triangular coronoid process. Neural 
arches of the cervical vertebrz high, and their spines well developed. 
Transverse process of atlas arising from upper two-thirds of side of 
the body, short, and deep from above downwards (figs. 10,11). On 
the hinder border of the under surface a median pointed triangular 
process, directed backwards and articulating with the axis. Upper 
* A specimen (Physalus sibbaldit, Gray) in the museum of the Hull Philoso- 
phical Society is said to have sixteen pairs of ribs—the highest number recorded 
in any Whale. If constant to the species, a modification of the above generic 
character will be required. 
