NOTES ON A PORPOISE OF THE GENUS PRODELPHINUS FROM THE 
HAWAIIAN ISLANDS. 
By FREDERICK W. TRUE, 
Head Curator of the Department of Biology , U. S. National Museum. 
Daring the investigations carried on under the direction of Dr. Jordan and Dr. 
Everniann by the U. S. Fish Commission steamer Albatross in the Hawaiian Islands 
in 1901, two specimens of a porpoise were obtained at Honolulu. The two heads, 
together with the pectoral fins, dorsal fin, flukes and a drawing of one of the speci- 
mens, made by Mr. A. H. Baldwin, June 7, 1901, were turned over to me by Dr. 
Jordan, with the request that I should report upon the material. 
A preliminary examination of the heads showed that they belonged to a species of 
Prodelphinus. After carefully measuring the heads and taking notes on the color- 
ation, I had the skulls extracted and cleaned. The specimen consisting of the head 
alone was numbered 112832, U.S.N.M., and the one comprising the head, pectoral 
and dorsal fins, and flukes, 112833, U.S.N.M. Plate 1 represents No. 112833. 
No. 112832, U.S.N.M., head. — The skin of the head is cut off about 2 inches behind the eye. 
Light yellowish-gray color from farther back and below runs forward to about the line of the eye (on 
the right side) where it is quite abruptly cut off by a darker tint which goes forward nearly to the 
stop. 0 The same occurs on the left side but is much more obscure. The darkest of these tints is still 
lighter than the blackish color which occupies the center of the head from the stop backward. This 
blackish color forms a triangular median area with the apex at the stop. On the right side over the 
eye its margin is 2J inches above the eye. The snout proper is blackish, except on the edges, where 
it is irregularly yellowish white with small, distinct, irregularly placed, quite black spots. A narrow 
band, quite black, starts from the stop, soon divides, and, passing back, the two divisions inclose the 
eye. The two divisions subdivide into two or three narrower lines with light lines between them. 
A similar black and a whitish fine line pass from the stop to the corner of the mouth. 
On the left side the colors are much darker and the lines are very obscure. 
A fine line, lighter than the surrounding color, passes from each side of the blowhole to the stop. 
The light color from the pectoral region passes forward underneath on the chin to a point in the 
median line 8J inches from the tip of the mandible. In advance of this the under side of the mandible 
is very dark yellowish gray, almost black. On the light-gray part of the throat are numerous small, 
elliptical, dark-gray spots, the largest of which are about three-eighths of an inch long. These can be 
seen also on the dark part of the mandible. The lower lips are yellowish white, like the upper, with 
scattered, small, quite black, spots. 
No. 112833, U.S.N.M., head, fins, and flukes. — The color is like that of No. 112832, but the mark- 
ings are more distinct. A blackish cap on the head from the stop broadening out posteriorly. The 
margin on the right side is 3 inches above the eye. Below this margin on the right side over the eye 
a The point where the convex outline of the forehead meets the base of the beak. 
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