BBY Prof. J. Reinhardt on the Fin- Whale 
from the figure representing this bone (fig. 4) seen from 
the concave upper surface, one-eighteenth of the natural size. 
Unfortunately the stylo-hyals, which sometimes seem to afford 
valuable specific characters, are wanting. 
The results to which we are led by examining the skull, the 
atlas, and the hyoid are moreover corroborated by the informa- 
tion received from Capt. Bottemann about the number of the 
ribs and of the vertebree ; for this gentleman, who last summer 
(1867) was occupied at the fishing-establishment at Seidisfjord, 
on the east coast of Iceland, counted sixty-four vertebree 
in the skeleton of a full-grown “ Steypireyér.” He found, 
further, fifteen pairs of ribs in a foetus about 18 feet long, 
which he had an opportunity of examining more minutely on 
the 2nd of September, and of which he has been kind enough 
to send a sketch, accompanied with numerous measurements. 
Accordingly, though important diagnostic parts of the skeleton 
(viz. the lower jaw, the first rib, and the sternum) have not 
been examined, yet it may be considered certain that the 
“ Steypireydr’”’ belongs to that section of fin-whales for which 
the Balenoptera antiquorum may be taken as the type, or, in 
other words, to the genus Physalus, Gray, 1864 (not 1866). 
But it is equally certain that it is a species not less distinct 
from the typical one as to its osteology, and especially as to its 
skull, than we know it to be as to its external characters. 
When we compare one or another of the better figures of the 
skull of the type with that of the “Steypireyér” (fig. 2), 
it will immediately be seen that the principal difference is 
that the beak (or, in other words, that part of the face which 
is situated before the orbital or zygomatic processes of the 
maxillaries) is much broader and much more obtuse in front 
in the “ Steypireyér” than in Balenoptera antiquorum, and 
that the outer borders of this part of the skull run almost 
parallel in their posterior half, and only begin to curve to- 
wards each other beyond this point. But this, on the other 
hand, is a diagnostic character of the skull of Balenoptera 
Sibbaldit. 
An additional resemblance to the latter species is further 
presented in the orbital processes of the frontals, whose breadth 
at their base is considerably greater than their length in the 
transverse direction of the skull. A pervading resemblance 
to this species in almost all the proportions of the skull 
will easily be proved by the table below, giving the measure- 
ments of the skull of the “ Steypireydr” taken exactly as 
Mr. W. H. Flower measured the skull of Balenoptera Sib- 
baldit formerly belonging to Lidth de Jeude; in which, 
further, the corresponding measurements of that skull are 
