88 MARINE MAMMALS OF THE NORTH-WESTERN COAST. 
SECTION II. -THE ORCA, OR KILLER. 
(Plate xvii.) 
The Orca — a cetaceous animal, commonly known as the "Killer" — is one of 
the largest members of the Dolphin family. The length of the adult males may 
average twenty feet, and the females fifteen feet. The body is covered with a 
coating of white fat, or blubber, yielding a pure, transparent oil. An extremely 
prominent dorsal fin, placed about two -fifths of the length of the body from the 
end of the animal's beak, distinguishes it from all other Dolphins. In the largest 
species (Orca redipinna) this prominent upper limb stands quite erect, reaches the 
height of six feet, is dagger- shaped, and frequently turns over sideways at . its 
extremity. In the animals of more moderate size, the fin is broader at the base, 
less in altitude, and is slightly curved backward, while upon others it is shorter 
still, and broader in proportion at its junction with the back, and is more falcated. 
The Orea redipinna, so far as we have observed, is more slender in its propor- 
tions, and is less marked with white or light spots than the others. It is usually, 
in color, jet-black above and lighter below; yet many of inferior size are most 
beautifully variegated, the colors being almost as vividly contrasted as in the stripes 
of the tiger of India. Some individuals have a clear white spot, of oblong shape, 
just behind the eyes, and a maroon band, of nearly crescent shape, adorning the 
back, behind the dorsal fin, which it more than half encircles. In others, the 
marks behind the eyes and dorsal are of a yellowish tinge, and usually, when this 
occurs, a small patch of light shade borders the semicircled exterior spout -hole. 
The dorsal band is somewhat pointed at the centre of its convex side, and, when 
looked at from behind the creature, nearly assumes the form of a heart. The 
under side of the pectorals and the caudal fin are generally of a milk-white or 
cream color, bordered by a darker shade ; and the nether portion of the body is 
white, with patches of the same color edging the sides. The head of the Orca is 
more pointed than that of the Blackfish (Globiocephalus), but less so than that of 
the Bay Porpoise (Pliocmna vomerina), to which it bears a resemblance. Its eyes 
appear sharp and prominent in comparison with other Cetaceans, which in a modified 
degree indicates the animal's disposition. Its mouth is armed with strong, sharp, 
conical teeth, which interlock, like those of the smaller Dolphins,* and its whole 
*In the head -bones of two specimens which the upper and lower jaws, were, respectively, 
we examined, the number of teeth on each of twelve and thirteen. 
