472 MR. W. H. FLOWER ON PHYSALUS SIBBALDII. [June 13, 
38. On PHYSALUS SIBBALDII, GRAY. 
By W. H. Fuower, F.R.S., Etc. 
This species of Fin-Whale was founded by Dr. Gray (Proc. Zool. 
Soc. 1847, p. 92) upon a skeleton preserved in the Museum of the 
Literary and Philosophical Society of Hull, which up to the present 
time has remained the only known representative of the species. 
Passing through Hull a few days‘since, I availed myself of the op- 
portunity of examining the skeleton, not perhaps with sufficient 
minuteness to be able to give a detailed description of its osteological 
characters, but closely enough to satisfy myself upon two important 
points,—first, that it is quite distinct from the Common Fin- Whale 
(P. antiquorum, Gray) ; secondly, that it agrees very closely with 
the specimen recently acquired by the Trustees of the British Mu- 
seum, from the collection of the late Professor Lidth de Jeude, of 
Utrecht, to which I have given the name of P. latirostris (Proc. 
Zool. Soc. 1864, p.410). The two specimens certainly belong either 
to the same species, or to two nearly related species forming a dis- 
tinct section of the genus. As the former supposition is probably 
the correct oue, I lose no time in withdrawing the specific name of 
latirostris‘in favour of the prior one given by Dr. Gray. 
I will now give a sketch of the principal characters of the two 
skeletons, showing where they agree with each other, and differ 
from P. antiquorum. 
1. Size—The Hull and the Utrecht skeletons are at nearly the 
same stage of growth; the epiphyses are disunited in almost all the 
vertebree, as well as on both ends of the humerus, radius, and ulna. 
In the Hull specimen the ossification of the transverse process of the 
second cervical vertebra has proceeded so far as to surround the 
vertebral foramen ; in the Utrecht skeleton the foramen is still open, 
though only by a narrow fissure on one side. I should judge from 
this that the former is rather the older of the two. In both, the 
transverse processes of all the remaining cervical vertebrae are incom- 
pletely ossified, and not united at their ends by bone. In general 
size and proportions the two specimens very nearly correspond, the 
advantage being in favour of the Hull one, which is stated to have a 
total length of 47 feet, the cranium being 10! 6'; while the Utrecht 
specimen is about 43 or 44 feet long, the skull being 9'10". Either 
example when full-grown would probably be not far short of 60 feet, 
or somewhat less than the average size of the common species. 
2. Number and Characters of the Vertebra.—-The two skeletons 
agree in possessing sixty-four vertebrae, both being in this respect, - 
fortunately, complete. In P. antiqguorum the number never appears 
to exceed sixty-two. In the Hull skeleton the foramen in the 
transverse process of the axis is very small, and nearly circular, 
about 2" in diameter; in the Utrecht specimen it is more oval, 33" 
high, and 43" long. This difference in so variable a part is proba- 
bly only individual. The four following vertebree have in both a 
converging upper and lower process, which are, as said before, in- 
complete and ununited. In the Hull specimen the seventh has a 
