WHALES AND PORPOISES 37 



is carried much further forward than in any other existing whale, 

 and is immediately over the tip of the upper jaw. The lower 

 jaw is quite slender towards its tapering end, but the upper jaw 

 terminates outwardly in an enormous truncated mass, rising 

 vertically above its attenuated bony termination. This truncated 

 snout is flat and broad, and its termination is almost square 

 with the sides of the head, though it is somewhat rounded 

 above. There is no indication of this extraordinary development 

 of gristle, flesh, and blubber in the skull of the sperm whale. 

 From the attenuated upper jaw one would argue a long, thin 

 beak instead of this gigantic snout, in shape like a huge travelling 



Skull of Sperm Whale (Physeter macrocephalus). 



bag. The eyes are placed not very far from the angle of the jaw, 

 and relatively close to the eye is situated the flipper, which must 

 be of httle functional use to the sperm whale. All the neck 

 vertebrae are fused together, and the neck is extremely short. 

 In the attachment of the ribs to the vertebras, the double head 

 of the rib may rest on a single vertebra. The blow-hole, 

 or outer termination of the nostrils, which, as in all the 

 Odontocetes, is a single opening, lies on one side of the termina- 

 tion of the snout, and not exactly in the middle. This makes 

 the upper surface of the skull markedly asymmetrical. The 

 aperture of the blow-hole is almost in the form of the letter S. 



