The St. George Island specimens were reported to be black on the back and
white below, but it is not certain how long they had been dead when found
by Mr. Judge. The young individual examined by Doctor Stejneger was also
black on the back, but this was in a state of decomposition.
The color of the type-specimen of _Berardius arnuxii_ was described by
Arnoux as follows: “Its color was entirely black, except for a light gray
area near the genital organs; it was a male.”[54] Haast remarks of a
young individual observed by him near New Brighton, New Zealand, and not
in a fresh condition: “The color of the whole animal was of a deep,
velvety black, with the exception of the lower portion of the belly,
which had a grayish color.”[55]
The color of the immature male of _B. arnuxii_ captured in Wellington
Harbor, New Zealand, in 1877, and described by Hector, was as follows:
“The colour was black with a purple hue, except a narrow band along the
belly, which was grey. The muzzle, flippers, and tail lobes were
intensely black.”[56]
It is not likely that there is any marked difference in the color of
_arnuxii_ and _bairdii_, but the data available are insufficient for the
determination of the matter. It will be observed, however, that Mr. Judge
stated that the male _bairdii_ found on St. George Island was white
below, while in all the accounts of _arnuxii_ the color of the under
surface is given as blackish, with a restricted area of gray.
Besides its apparently greater size, _Berardius bairdii_ differs from _B.
arnuxii_ in various cranial and other osteological characters, as well as
in external proportions, and is to be regarded as a distinct species. The
external measurements of the St. George Island specimens reduced to
percentages of the total length and compared with similar measurements of
a specimen of _B. arnuxii_ described by Hector, are as follows:
_External dimensions of Berardius bairdii and B. arnuxii._
Column Headings:
_bairdii._
A: 49726 St. George Island, Alaska, (Judge), female adult.
B: 49727 St. George Island, Alaska, (Judge), male imm.
_arnuxii._
C: Wellington, New Zealand, (Hector), male.
Measurements. A B C
ft. in. ft. in. ft. in.
Total length 40 2 25 5 27 6
per per per
cent. cent. cent.
Distance from tip of snout to blowhole 10.8 11.8 12.8
Distance from tip of mandible to corner of 6.0 6.9 [a]6.1
mouth
Breadth of flukes from tip to tip 25.3 24.6 19.1
Length of pectoral fin along outer edge 12.4 13.4 9.4
Distance from anus to “end of body” 29.0 29.8 [34.0]
Height of dorsal fin 2.5 2.4 3.0
Distance from anterior base of dorsal fin to 29.7 29.2 [34.6]
“end of body”
[a] “Length of gape.”
The measurements of these specimens of _bairdii_ agree well together. The
specimen of _arnuxii_ appears to have had narrower flukes, shorter
pectoral fin, and a rather higher dorsal fin, situated farther forward
than in _bairdii_. Measurements of a larger number of specimens might
show that some or all of these differences of proportion are elusive, but
it will be observed that in the Wellington specimen of _arnuxii_,
recorded by Doctor Haast, the breadth of the flukes is only 21 per cent
of the total length. The pectoral fin is said to be only 19 inches long,
or only 5.2 per cent of the total length, but the manner of taking the
measurement is not mentioned.
As regards size, the largest specimen of _B. arnuxii_ of which I find
record is the type specimen. This was 32 feet long, and the skull 1,400
mm., or about 55 inches long. This appears to have been an adult male.
The Centerville specimen of _bairdii_, which was an adult male, was about
41 feet long, and the skull 1,532 mm., or about 60 inches long, while the
adult female from St. George Island was 40 feet 2 inches long and the
skull 56 inches. Although the total length of the specimens of _bairdii_
is so much greater, it will be observed that the length of the skull,
while a little greater, absolutely fails to measure up to the proportions
found in _arnuxii_. It might be suspected on this account that the
external measurements of _bairdii_ were exaggerated, but that such is not
the case will appear from an examination of the measurements of vertebræ
given on page 75. It is evident that the specimens of _bairdii_ are far
more massive in all parts of the skeleton than the specimen of _arnuxii_
there cited. The same relations will be found upon comparing measurements
of the specimen of _arnuxii_ figured by Van Beneden and Gervais.[57] The
truth appears to be that _bairdii_ is a much larger species, but that the
skull is considerably smaller relatively.