672 NATUEAL HISTOET OP AQUATIC ANIMALS. 



The Thkasher Shaek — Alopias vulpes. 



The Thrasher Shark, known in Europe as the "Fox Shark," and to our fishermen most usually 

 as the "Swingle Tail," is found in the Northern Atlantic and in the Mediterranean, and also off 

 California. It is one of the most grotesque of sea animals, the upper lobe of the tail being 

 exceedingly long, curving upwards and resembling in form the blade of a scythe. 



The Thrasher attains the length of fourteen or fifteen feet and the weight of five hundred 

 pounds. An individual was taken in November, 1864, in the harbor of Marion, Massachusetts, 

 which was thirteen feet long and weighed four hundred pounds. This species is quite common all 

 along the coast of New England, and is frequently an annoyance to the mackerel fishermen by 

 becoming entangled in their nets; otherwise it is quite harmless. It is found also in California. 



The tales which are current regarding the ferocious attacks of these Sharks upon whales are 

 apparently without foundation. 



These animals feed upon fish, and it is said by the fishermen that they kill them by blows of 

 the long, flexible tail. When they become entangled in the nets, or are caught on hooks, they 

 make a powerful resistance and cause th« fishermen much trouble. Their livers are sometimes 

 used by the oil-makers. There is a belief widely current to the effect that the Thrasher Shark, 

 singly or in companies, is accustomed to attack whales. This belief is undoubtedly founded upon 

 errors of observation, as I think I have demonstrated in the chapter relating to the Sword-fish. 



The Hammer-head Shark — Sphyrna zyg^na. 



This species is found all along the coast from Cape Cod southward, and, indeed, in tropical 

 and subtropical seas the world over ; it may be easily recognized by the curious form of the head, 

 which is broad, flattened, and laterally elongated into two arms, which have been compared to 

 the arms of a balance. It attains the length of seven or eight feet. Dillwyn obtained a female 

 specinjen at Swansea, which contained thirty-nine young ones on the point of birth. 



The Hammer-head Shark is not uncommonly taken in summer, but is of no special impor- 

 tance. In Mitchill's "Fishes of New York," under the head of this species it is stated: "Three 

 Sharks of the Shovel-nosed species were taken (in September, 1805) in a net by Mr. Joshua Turry, 

 of Eiverhead. The largest was eleven feet long. On opening him, many detached parts of a man 

 were found in his belly; these were collected and buried; there was also found a striped cotton 

 shirt, patched on the sides and sleeves with bright-colored pieces."^ 



It seems probable that the Shovel-nosed Shark referred to in the above paragraph was rather 

 a Garcharias, since these Sharks are often called " Shovel-nosed Sharks " by the coast fishermen. 



Bonnet-headed Shark — Sphyrna tiburo. 



This species is found in our waters in company with the preceding species, and when both are 

 known to the fishermen, the names "Hammer-head" and "Shovel-nosed" are used indiscrimi- 

 nately for both. Its distribution as at present understood is less extensive, since it has been found 

 only in the warmer parts of the Atlantic and on the coast of China. It is very common on our 

 South Atlantic and Gulf coast, where it is often distinguished as the "Bonnet-head." The habits 

 of the two species are doubtless very similar. 



The Blub Shark and the Dusky Shark — Caecharias c^euleus and Carcharias 



obsourus. 



These two species, which are somewhat common in our waters south of Cape Cod and which 

 can be distinguished apart only by trained observers, attain the length of twelve or fifteen feet, 



' Transactions of Literary and Philosophical Society of New York, i, p. 48. 



