THE SHARKS; SPINACID^; GALEIDJB ; LAMNIDJE. 35 



length of about fourteen feet, and is a deadly enemy to the 

 Whales, attacking and biting them with great severity. It ap- 

 pears to feed to a great extent upon the floating carcases of 

 these gigantic Mammalia, biting large pieces out of them witli 

 its enormous jaws, which measure nearly two feet across. It is 

 a constant attendant upon the Whalers when they are engaged 

 in cutting up their captures, but never appears to touch the 

 men, although they often slip into the water amongst a crowd of 

 Sharks. Its tenacity of life is very remarkable. The Greenland 

 Shark is very subject to be attacked by a parasitic animal, be- 

 longing to the class of Crustacea, which attaches itself to the 

 eyes. The parasite measures from one to two inches in length, 

 and its almost constant presence may give some countenance to 

 the belief of the Whalers that the Shark is blind, as it never 

 attempts to escape from a threatened blow with a lance or 

 knife. The Greenland Shark sometimes occurs near the north- 

 ern coasts of this country. 



586. The SPINACID^E, or Picked Dogs, resemble the preceding 

 Fishes in most of their characters, but have the dorsal fins furn- 

 ished with a strong spine. The common Picked Dog-fish of our 

 seas is so abundant, that as many as twenty thousand of them 

 have been taken in one seine. It is about three feet long, and is 

 said to be good food. The Picked Dog is also said to employ 

 the spines of his dorsal fins as weapons, by bending himself into 

 the form of a bow, and then striking out with great force. The 

 GALEID^E, or Topes, are distinguished from the preceding by 

 the possession of an anal fin, and the absence of spines in the 

 dorsals ; their caudal fin is very unsymmetrical. Two species, 

 the common Tope and the Smooth Hound, are abundant in our 

 seas ; the former has triangular, sharp, serrated teeth, like those 

 of the rest of the Sharks ; but the latter has the jaws covered 

 with a sort of mosaic, as in the Rays, and, like these, it feeds 

 principally on Crustacea. 



587. The LAMNID.E, or Porbeagles, have the tail nearly 

 symmetrical, two unarmed dorsal fins, an anal fin, and two large 

 spiracles ; the branchial apertures are all placed in front of the 

 pectoral fins. The snout is of a pyramidal form. The common 



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