SHARK. 



659 



hard and tasteless ; but still it is better than absolute 

 hunger. Then, when they are abundant, the offal 

 is of use in enriching the fields. 



CENTRINA. This genus have spines on the back 

 as well as the last, bnt the one is directed forwards 

 and the other backwards. They have several rows 

 of small pointed teeth in the upper jaw, and one or 

 two rows of cutting teeth in the lower ; they have the 

 tail very short and the body massive, a sort of trian- 

 gle in the section, the lower part of the fish forming 

 the base of the triangle ; they have the habit of lurk- 

 ing in the mud at the bottom, for which reason they 

 are sometimes called sea-hogs. It is probable that, 

 while they lie in this manner, they wait for prey, 

 which they first wound with the dorsal spines, and 

 then seize with the mouth. They are found both in 

 the Mediterranean and the Atlantic ; but there is no 

 mention of them even as stragglers upon the British 

 coasts. They are fishes of little interest, as they are 

 of small use, and do less harm than the dog-fish. In 

 consequence of their lurking habits, they are seldom 

 caught or even seen. 



SCYMNUS. Some species at least of this genus are 

 better known and possess a higher degree of interest 

 than the preceding one. In the characters of the 

 mouth they are nearly the same, having several rows 

 of sharp-pointed teeth in the upper jaw, and two rows 

 of cutting ones in the under ; the first dorsal fin is 

 placed near the middle of the length of the body ; 

 there is no anal fin, and the tail is rather short. 

 Some species of this genus occur in the seas of the 

 southern hemisphere, and there is one in the north, 

 which is a large and powerful fish, and among the 

 most polar in its locality of any of the shark family. 

 This one is 



The Greenland Shark (S. borealis}. This has been 

 named in the lists as a British fish, but on very slen- 

 der grounds ; for the two that have been mentioned 

 did not come even as living stragglers, but were cast 

 on the shore. Farther to the south it has never been 

 observed, even in the state of a wreck, drifting before 

 the current of the water. Its colour on the upper 

 part wants the brownish tinge, but otherwise it is not 

 very unlike that of the great white shark of the warm 

 latitudes ; but the shape is like that of the prehensile. 

 In consequence of the similarity to the white shark, 

 when seen at a distance, this Greenland one was long 

 considered as being either the same or a variety ; 

 and thus, though it is a large and powerful fish, it 

 has got a character for voracity which it probably 

 does not deserve to the full amount that has been 

 stated. 



The best, and indeed the only good account of 

 the Greenland shark which has been given from 

 actual observation, is that in Scoresby's work on the 

 Arctic Regions, which we shall quote : " The Squa- 

 /us borealis is twelve or fourteen feet in length, some- 

 times more, and six or eight feet in circumference. 

 The opening of the mouth, which extends nearly 

 across the lower part of the head, is from twenty-one 

 to twenty-four inches in width. The teeth are ser- 

 rated in one jaw, and denticulated in the other. It 

 is without the anal fin, but has the temporal opening; 

 the spiracles on the neck are five on each side. The 

 colour is cinereous grey. The irides are blue ; the 

 pupil emerald green. 



" This shark is one of the foes of the whale. It 

 bites and annoys it while living, and feeds on it when 

 dead. It scoops hemispherical pieces out of the 



body, nearly as big as a person's head; and continues 

 scooping and gorging lump after lump until the whole 

 cavity of its body is filled. It is so insensible of pain 

 that, though it has been run through the body and 

 escaped, yet, after a while, I have seen it return to 

 banquet on the whale, at the very spot where it re- 

 ceived its wounds. The heart is very small ; it per- 

 forms six or eight pulsations in a minute, and con- 

 tinues beating for some hours after taken out of the 

 body. The body also, though separated into any 

 number of parts, gives evidence of life for a similar 

 length of time. It is therefore extremely difficult to 

 kill. It is actually unsafe to trust the hand in its 

 mouth, though the head be separated from the body. 

 Though the whale-fishers frequently slip into the 

 water where sharks abound, there has been no in- 

 stance, that I have heard of, of their ever having 

 been attacked by the shark. 



" Besides dead whales, the sharks feed on small 

 fishes and crabs. A fish, in size and form resembling 

 a whiting, was found in the stomach of one that I 

 killed ; but the process of digestion had gone so far 

 that the species could not be satisfactorily discovered. 

 In swimming the tail only is used ; the rest of the fins, 

 being spread out to balance it, are never observed to 

 be in motion but when some change of direction is 

 required." 



There is the foundation of much knowledge in this 

 passage ; and if the other inhabitants of the deep 

 could be examined as closely, and described as well, 

 our knowledge of fishes would assume a very diffe- 

 rent character from what it has at present. 



Insensible as the Greenland sharks are to pain, 

 and formidable as they are to the whale, they are not 

 without their enemies, of a description against which 

 their powers are not of the slightest avail. Captain 

 Scoresby found attached to the eye of the shark a 

 white worm-shaped substance about two inches in 

 length, terminating in two filaments. On examina- 

 tion this was found to be a species of Lertuea, a 

 parasitical zoophile, various species of which torment 

 fishes by attacking their gills, their eyes, and other 

 delicate parts of their structures. 



There appear, from the reports of naturalists who 

 have visited the South Sea, to be sharks there which 

 agree with the Greenland shark in some particulars, 

 but differ from it in others. 



ZYG^NA Yoke-headed or hammer-headed sharks. 

 These have many of the characters of the genus Car- 

 charias ; but the form generally is very unlike them, 

 and the head is so singular as to have no parallel in 

 the whole animal kingdom, many and varied as are 

 its members. These curiously-formed fishes appear 

 to be widely distributed, being found in the seas both 

 of the north and the south ; and one specimen is 

 recorded as having been taken at Yarmouth in 1829. 

 Four spe.ies have been described, and there are pro- 

 bably many more, but we must confine our notice to 

 one. 



The common hammer-headed Shark (Z. malleus). 

 This species grows to the length of twelve or four- 

 teen feet. The body is rounded in its section, 

 spindle-shaped, with the thickest part behind the first 

 dorsal fin, and the tail very long ; the pectoral fins 

 are large, originating immediately in the rear of the 

 last gill-opening, convex on their anterior margins, 

 concave on their posterior, and pointed. The first 

 dorsal is nearly opposite to them, of considerable 

 size, and with a deep curved notch in the extremity. 

 TT 2 



