128 GRAMPUS.-NATUVKAL. CACHALOT. 



39. The Common Porpoise, Dc.lphinus Phoccena^ (Plate 6. 

 fig. 6.) which is the smallest of all the Cetac?a, never exceeds 

 four or five feet in length. It lives in numerous troops. 



40. Another species of Porpoise known under the* name of 

 Grampus, Delphiniis G/adiflor, is the largest animal of this 

 tribe of Cetacea, often attaining from twenty to twenty-five feet 

 in length. It is the most relentless enemy of the whale. They 

 attack it in troops, and torment it until it opens its mouth, when 

 they devour the tongue. 



41. The NARWHALS, Monodon, closely resemble porpoises, 

 but they have no teeth properly so called. The mouth is armed 

 with two straight, horizontal tusks, one of which generally re- 

 mains concealed' in the alveolus while the other acquires a very 

 considerable length, sometimes ten feet, and is generally furrowed 

 spirally. These. tusks were for a long time mistaken for the 

 horns of a fabulous quadruped, the Unicorn Only one species 

 of Narwhal is known : it inhabits the North Sea, principally be- 

 tween Greenland and Iceland. Its skin is marbled brown and 

 whitish, and its length is from fifteen to sixteen feet. Its vent is 

 on the top of the head, and it has no dorsal fin. It swims with 

 great rapidity, and is a formidable enemy of the whale, which it 

 attacks in troops, inflicting deep wounds with its tusks Fisher- 

 men seek it for the excellent oil obtained from its fat, a single 

 Narwhal yielding from two to three tons. The tusks are also 

 employed for the same purposes as ivory. 



42. The CACHALOTS, Physeter, ( Plate 6, fig. 9,) -are 

 Cetacea with a very voluminous, inflated head, particularly in 

 front, whose lower jaw is armed with a row of cylindrical 

 teeth, which, when the mouth is closed, enter into corresponding 

 cavities in the upper jaw which has neither teeth nor whale- 

 bone, (balen.) The head of these animals is enormous, and very 

 much swelled-out anteriorly. Its structure is very singular; all 

 above the face and cranium is formed into a large oval basin, the 

 edges of which rise behind six feet above the cranium and gradu- 

 ally diminish in front ; the parietes of this great cavity are chiefly 

 formed by a prolongation of the superior maxillary bones, which 

 joins a vertical crest of the occipital bone, and these latter give in- 



39. Wh;it is the common Porpoise? 



40. What is the Grampus? 



41. What are Narwhals? What is the Unicorn ? To what purposes are 

 Narwhals applied ? 



42. What are Cachalots ? What kind o** teeth have they ? What is the 

 rze of their head? What are the anatomical peculiarities of the head of 

 Hie Sperm Wnale ? In what part of the animal is spermaceti found 7 



