BLUE SHARK. 383 



line of the anterior edge of the pectoral fin ; the pectoral fins 

 large and falciform ; the body of the fish deepest in the line 

 of their origin, but becoming more compressed and tapering 

 from thence to the tail ; the first dorsal fin situated over the 

 space between the pectoral and anal fins, rather small, low 

 and rounded above, with a horizontal projecting elongation 

 at the base behind : the ventral fins small, obliquely truncat- 

 ed, and placed under the space between the first and second 

 dorsal fins ; the anal fin placed half-way between the ventral 

 fins and the lower lobe of the tail, opposed to or under the 

 second dorsal fin, and each ending in a prolongation directed 

 backwards ; the tail divided, the upper lobe two- thirds longer 

 than the lower, the vertebral column continued along it ; the 

 inferior lobe somewhat triangular in shape ; the upper lobe 

 falciform, and with an extension of the membrane towards the 

 extreme end. 



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 150. 



