Abstract

(…) This peculiar species of Dolphin is the least in size of the entire whale tribe inhabiting the Pacific North American Coast. When fully matured it may attain the length of six feet, but those we have had opportunity to measure fell considerably short of these dimensions. Usually the adults are not more than four and one-half feet between linear extremes. The body of the male is jet black above, a little lighter below; and while the female is of the same color above, it is lighter on the sides, with a narrow black streak running from the corner of the mouth to the pectorals, and the lower portion of the animal is of a milky whiteness, yet the pectoral and caudal fins are black underneath, or of a dark gray. Occasionally, however, both males and females are found with the larger portion, or the whole, of their dorsal and caudal fins white. The former are of triangular shape, and placed very nearly midway between the animal’s extremities. The caudal fin varies much in its contour, sometimes being quite broad and straight on its posterior edge, which is slightly notched in the centre; in other specimens the caudal lobes are Iunate, and united present a forked appearance. Its pectorals are extremely small and placed low. Its head is somewhat pointed, but destitute of the slender, elongated beak of the Delphinus Bairdii, and the Right Whale Porpoise. The anterior portion of the animal resembles that of both the Orca and the White-headed Grampus. Its eyes are placed about two inches behind the corner of the mouth, and nearly in a line with it. Its ears are two inches from the eyes, and these minute orifices would not be noticed by the casual observer, as they are less than a sixteenth of an inch in diameter. The spiracles are placed a little forward of the eyes, and unite in one where they pass through the fleshy part of the cranium. The valve which covers them is convex on its posterior side. When the animal respires this valve is turned downward. Both upper and lower jaws are furnished with teeth, which in the adults are thin, flat, and broadest near their summits. In one example, a female four feet long, taken at San Francisco, California, the number was 26/24, and in another, 21/24. In a male, four feet eight inches in length, taken in Port Townsend Bay, Washington Territory, the number was the same as last mentioned. (…)