34 FISHES OF THE VICINITY OF NEW YORK 



BLUE SHARK 



further back, halfway between the breast and belly fins. The Tiger 

 Shark, reaching a much larger size than any of the above, is a rare 

 straggler from the south. Its head is blunt, shoulders heavy, body 

 slender and tapering. All but the very large ones are marked with 

 numerous dark spots. The teeth are characteristic, very broad with 

 rounded coarsely serrate sides, and oblique pointed tips, the teeth of 

 the upper and lower jaws alike. -The Hammerhead Shark has the sides 

 of the head peculiarly produced like the head of a flat hammer. It is a 

 swift and vigorous species reaching a large size and often seen at the 

 surface, not rare in this vicinity. Its peculiar head probably functions 

 as a bow rudder. The common Sand Shark bears a superficial re- 

 semblance to the Brown Shark but may be easily distinguished by the 

 large second back fin, little smaller than the first. Its teeth are very 

 sharp, white and cat-like, narrow, with small cusps at their bases. It 

 is generally smaller, three or four feet long, with black spots in life. A 

 large species occasionally found off shore is the Thresher Shark with tail 

 remarkably long and slender, about as long as the head and body. It 

 reaches a length of fifteen feet. 



The true tropical "Man-eater" or White Shark has never but 

 once been taken in this vicinity ; though it has occurred several times 

 further north. It belongs to a particularly swift swimming, voracious 

 group, with the tail fin more symmetrical, crescent shaped, better 

 developed below; and has a keel on the side of the tail like its smaller 

 relative, the Mackerel Shark, which has been taken in our waters. 

 The Mackerel Shark reaches a length of ten feet. Its first back fin is 

 large, placed about intermediate between the breast and belly fins; the 

 teeth are large, slender and sharp without saw edges or basal cusps, 

 while those of the Man-eater are triangular with saw edges. Large 

 specimens of the White Shark or Man-eater are lead white in color, but 

 smaller ones are dark above and white below. It is one of the largest, 

 most powerful of existing fishes. Dr. Jordan tells of finding a fair-sized 

 young sea lion whole in the stomach of one of about thirty feet. 



