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TEXT-BOOK OF ZOOLOGY 



and occasionally it will even attack man (man-eating sharks). Its 

 dangerous character in this respect has, however, frequently been much 

 exaggerated. 



(b) The body is elongated, and the tail, with its asymmetrical fin 

 (see pp. 267, 268), extremely powerful. These characters, especially the 

 last named, render the shark, in rapid swimming, a match for any other 

 sea-inhabiting animal. (Describe the other fins.) 



(c) The cartilaginous cranium projects anteriorly, so that the facial 



skeleton lies completely beneath it. Hence 

 the wide mouth is placed transversely across 

 the under side of the head. This position 

 of the mouth, however, is by no means an 

 advantage to the animal, more especially as 

 the jaws are not protrusible, as in teleostean 

 fishes (see p. 271). 



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Blue Shakk. (About one-fortieth natural size.) 



(d) This deficiency and the absence of an air-bladder are, however, 

 amply compensated by the remarkable poiver of movement of the animal. 

 On account of the cartilaginous skeleton, the body of the shark is flexible 

 from above downwards, as well as laterally ; and, as occasion requires it, 

 the fish rolls itself about its longitudinal axis, or throws itself on its back 

 with equal ease. 



(e) The mouth bristles with several rows of large, double-edged teeth 



