These three specimens were collected and presented by N. Grebnitzki.
13. Cat. No. 142579. A series of photographs of an individual captured in
Kiska Harbor, Alaska, September, 1904. Presented by Dr. J. Hobart Egbert.
14. Cat. No. 84906. Photograph of the skeleton of an individual washed
ashore at St. Simon Island, Georgia, in 1893, and belonging to Mr. W.
Arnold.
In the genus _Ziphius_, as in other ziphioid genera, a study of the
characters of the skull appears to afford the best basis for
discrimination of species. We have first to consider whether the North
American species is the same as the European and New Zealand species, and
afterwards whether the North Pacific species is identical with or
distinct from these.
The published measurements of specimens from the coasts of Europe and New
Zealand, currently believed to represent the single species _Z.
cavirostris_, are rather meager, and, furthermore, prove, on examination,
to present so little uniformity that they are of limited use for
comparison with measurements of skulls from the Atlantic coast of the
United States. About all that can be said is that the latter skulls are
of about the same size as the former and that the proportions do not
present any striking differences. For detailed measurements of the
American skulls, see page 53.
On account of the uncertainty as regards the measurements, I have had
recourse to the published descriptions and figures, especially those of
Van Beneden, Sir William Turner, and Doctor Haast. So far as I can
perceive, there is nothing in these descriptions that is not applicable
to the skulls Nos. 49599 and 20971, from Newport, Rhode Island, and
Barnegat City, New Jersey, respectively, in the National Museum, and I
can find no reason for regarding the latter other than as representatives
of _Z. cavirostris_.