CETACEA. 509 



whalebone is comparatively valueless, so that the whalers 

 rarely meddle with them, though they are not uncommon, and 

 are often driven ashore on our own coasts. 



Fam. 2. Catodontida. The family of the Catodontidcz or 

 Physeterida comprises the Sperm Whales or Cachalots, with 

 which we commence the series of the Toothed Whales ( Odon- 

 toceti). They are characterised by the fact that the palate is 

 destitute of baleen-plates, and the lower jaw possesses a series 

 (about fifty-four) of pointed conical teeth, separated by inter- 

 vals, and sunk in a common alveolar groove, which is only im- 

 perfectly divided by septa. The upper jaw is also in reality 

 furnished with teeth, but, with a single partial exception, these 

 do not cut the gum. 



Fig. 195. Spermaceti Whale (Physeter macrocefhalus). 



The best-known species of this family is the great Cachalot 

 or Spermaceti Whale (Physeter macrocephalus, fig. 195). This 

 animal is of enormous size, averaging from fifty to seventy feet 

 in length, but the females are a good deal smaller than the 

 males. The head is disproportionately large, as in the Balczn- 

 id(Z) forming nearly one-third of the entire length of the body. 

 The snout forms a broad truncated muzzle, and the nostrils 

 are placed near the front margin of this. The Sperm Whales 

 live together in troops or " schools," and they are found in 

 various seas, especially in the North Pacific. They are largely 

 sought after, chiefly for the substance known as " spermaceti ; " 

 but besides this they yield oil and the singular body called 

 " ambergris." The spermaceti is a fatty substance which has 

 the power of concreting when exposed to the air. It is 'not 

 only diffused through the entire blubber, but is also contained 

 in special cavities of the head. The sperm-oil yielded by the 

 blubber is exceedingly pure, and is free from the unpleasant 

 odour of ordinary whale-oil. The ambergris is a peculiar sub- 

 stance which is found in masses in the intestine, and is proba- 

 bly of the nature of a biliary calculus, since it is said to be com- 

 posed of a substance very nearly allied to cholesterine. It is 

 used both as a perfume itself, and to mix with other perfumes. 



