BLUE SHARK. 



501 



The whole of the upper surface of the head, back, both 

 dorsal fins, and most of the tail, are of a fine slate blue ; the 

 irides, upper surface of the pectoral and ventral fins, are also 

 blue ; the lower part of the sides, under surface of the head, 

 neck, pectoral fins, belly, ventral fins, and the anal fin to the 

 base of the tail, white. The skin of this Shark has a granu- 

 lated appearance on the surface, and is only slightly rough to 

 the touch on passing the finger in the direction from the tail 

 towards the head. 



For a reference to habits see volume i. page 171. in the 

 account of the Pilot-fish. 



The teeth represented below are the five first, and from 

 the outermost row in the upper and under jaw, beginning 

 from the centre of the mouth in front, and occupying a short 

 space along the left side. The teeth of the Sharks generally 

 diminish gradually in size from the front backwards, and when 

 they are pointed and curved, the point is directed backwards 

 on both sides of the mouth towards the posterior angle of the 

 gape. 



