CKTACEA. 549 



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. 213. — Spermaceti Whale {Physeter macrocepkalus). 



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

 or Spermaceti Whale (Fhyseter macrocephalus, fig. 213). 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 Balcsn- 

 idee, forming nearly one-third of the entire length of the body. 

 The snout forms a broad truncated muzzle, and the nostrils 

 .ire 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, being in life 

 a clear white oily liquid. 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 substance which is found in 

 masses in the intestine, and is probably of the nature of a 

 biliary calculus, since it is said to be composed of a substance 

 very nearly allied to cholesterine. It is uged both as a per- 

 fume itself, and to mix with other perfumes. 



Fam. 3. Z>^^/^W(2fe.— This family includes the Dolphins, Por 

 poises, and Narwhal, and is characterised by usually possessing 

 teeth in both jaws : the teeth being numerous, and conical in 

 shape. The nostrils, as in the last family, are united, but they 

 are placed further back, upon the top of the head. The single 

 blow-hole or nostril is transverse and mostly crescentic or lunate 



