38 BRITISH MAMMALS 



In the narrow lower jaw the number of teeth may be as many as 

 twenty-five. The two diverging bones which form this mandible 

 are united for more than half their course, and are not widely 

 separated from their junction at the chin, as is the case with 

 most other cetaceans. In the enormous cavity between the bones 

 of the skull and the upper surface of the trunk-like head is an 

 accumulation of oily matter — spermaceti — secreted by the lining 

 membranes of the great cells that surround the long passage 

 running diagonally through this huge excrescent growth from 

 the openings of the nasal bones in the front of the skull to 

 the outlet of the nostrils at the end of the snout. This whitish 

 oil, which is secreted on either side of the passage of the nostrils, 

 has been in use for hundreds of years for many purposes. Its 

 origin and nature were at first misunderstood by the ancients, 

 who thought that it was the seminal fluid of the whale and there- 

 fore called it " spermaceti." The thick blubber which lies all along 

 the back of the sperm whale also produces a most valuable oil, and 

 for these two products (together formerly with ambergris) the 

 sperm whale has been hunted well-nigh to extinction. Ambergris, 

 which is found in its intestines, and which, when expelled there- 

 from, floats on the surface of the sea, is a gummy substance in 

 which are embedded the beaks of cuttlefish. This substance is 

 used in perfumery, and anciently was thought to be a strong 

 aphrodisiac. The sperm whale has no back fin, but along the 

 line of the back there are a series of lumps and undulations. 

 The largest of these, which rises in the middle of the back over 

 the junction of the tail and the body, is almost prolonged into 

 a fin-like excrescence. The colour of the cachalot, or sperm 

 whale, is black, shading into a grayer tint on the belly. Its food 

 consists mainly of squids and cutdefish. It also eats such fish as 

 come in its way. 



The cachalot was formerly world-wide, with the exception 

 that it avoided the icy seas of the Arctic and Antarctic regions. 

 Sperm whales were repeatedly cast ashore on the coasts of Britain 

 in preceding centuries, the last occurrence, however, being no 

 farther back than 1871, when a large specimen was stranded on 



