88 MARINE MAM3IALS OF THE NORTH-WESTERN COAST. 



SECTION n.-THE ORG A, 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 rectipinna) 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 [Phoccena 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. 



