THE SQUALID^ OR SHARKS. 127 



half; and an entire human body is said to have been 

 found, on one occasion, in the stomach. Fortunately, 

 however, very few of those found in our temperate 

 latitudes grow to such a size as to awaken our fears, or 

 commit injury upon our persons ; but so soon as we 

 enter the warmer regions, towards the tropics, bathing 

 in the sea becomes a hazardous, and often a dangerous, 

 undertaking. The late sir Brook Watson is well-known 

 to have had his leg amputated by one single bite of a 

 shark, while bathing in the West Indies : and both 

 there, and on the opposite coasts of Africa, the ocean 

 swarms with them. A very few species, however, feed 

 upon animals that are already dead, and even upon 

 marine plants. They all swim with great velocity, and 

 often in vast multitudes, when pursuing shoals of other 

 fish. Our excellent ichthyologist, Mr. Couch, says he 

 has heard of about 20,000 of the picked dog-fish 

 (Spinax acanthias), having been taken in a Cornish 

 net, called a sein, at one time ; and such is the strength 

 of instinct, that young ones, not six inches long, are 

 found, in company with their parents, following shoals 

 of fish, on which, at that age, they could not prey.* 



(113.) The form of all the sharks is lengthened; 

 the body and fins being covered with a hard coriaceous 

 skin, often tuberculated, and sometimes intermixed with 

 spines or plates ; but none have been yet found with 

 true scales. The substance called shagreen is no other 

 than the prepared skin of these and other cartilaginous 

 fish, the different degrees of roughness indicating different 

 species. The head is always more or less flattened, 

 generally wider across than the body ; and sometimes, 

 as in the hammer-headed sharks, enormously dilated. 

 The snout, more especially, is dilated, and always ad- 

 vances t considerably beyond the mouth, which is thus 

 concealed beneath, and can only be seen, or indeed 

 used, when the fish is turned on one side : this is pre- 

 cisely the case with the rays ; and renders it necessary 



* Yarrell's Brit. Fishes, vol. ii. p. 401. 

 f Except in the most aberrant forms. 



