PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. CF 
a very inappropriate designation, as the teeth are situated on the tip of 
the lower jaw, and not on the nose. 
The second species, founded on my No. 1521, seems to belong to the 
Cuvierian genus Ziphius, having for its type Z. cavirostris Cuy., and 
more especially to the group (Petrerhynchus Gray) which is character- 
ized by having the nasals, in connection with the premaxillaries, formed 
to a vaulted roof over the nares, and the ethmoidal cartilage ossified 
and extending above the premaxillaries in the anterior part of the beak. 
I take great pleasure in “dedicating this interesting species to its dis- 
coverer, the obliging governor of the Commander Islands, Mr. Nicolaj 
Grebnitzky, to whom science is indebted for these and many other con- 
tributions, and myself for so much courtesy. I propose to name it 
Ziphius grebnitzkii. 
That the typical specimen is an old animal is evident from the fusion 
of the bones and the indistinctness of the sutures, thus making it some- 
what difficult to distinguish the individual bones. 
After my return from here I shall give a more complete description 
and figures; but in the mean time the following characters may serve 
for the identification of the species, as I consider most of them diagnostic: 
The tip of the beak is obtuse, with a vertical furrow in the middle, 
the lower jaw with the two terminal teeth protruding considerably be- 
yond the upper one. From about the middle of the beak towards the 
tip the mesethmoidal, ossified in its whole length, arises, like a rounded 
staff, between and above the premaxillaries, following these to the tip 
and being totally fused together with them. The nasal groove is very 
unsymmetrical, owing to a very prominent asymmetry of the premaxil- 
laries and the nasals, so that the direction of the oblique nares forms 
an angle of not less than 20 degrees with the vertical plane through 
the longitudinal axis of the skull. The right os nasale and the pre- 
maxilla of the same side are by far the larger ones, and form the prin- 
cipal part of the roof above the nares, the nasal not reaching, however, 
so far forward as the premaxilla. The antenasal groove is large, and 
in the anterior half partly vaulted over by the edges of the premaxil- 
laries, which are somewhat bent inwards. 
The zygomatic process of the squamosals touches the orbital process 
of the frontals without coalescing, however. The jugale is not nar- 
rower in the fore part, which, consequently, is not dilated and does not 
reach the posterior maxillary notch. This is not particularly deep, and 
the anterior one is still more shallow. The visible part of the vomer is 
long and narrow, commencing 124"™ (4.88 inches) from the tip of the 
beak. The supraoccipital is rather inclined forwards, forming an angle 
of about 40° with a line parallel to the vertical axis of the skull. 
The following table of dimensions contains the mere important meas- 
urements in millimeters and English inches: 
