ORDER II. 



CHONDROPTERYGII BRANCHIIS FIXIS. 



Family I. 

 SELACHII. 



Carcharias. Cuv. 



Generic characters. Jaivs and head depressed; nostrils 

 pierced in front ; teeth pointed and cutting, often serrated at 

 the edges ; first dorsal fin large and placed beJdnd the pecto- 

 torals and before the ventrals ; pectoral fins large. 



C. vulpes. Lin. The Fox Shark. Thresher. 



Turton's Linnaeus, vol. i. p. 918. 



Pennant's British Zoology, vol. iii. p. 97 et fig. 



Trans. Lit. et Philosoph. Soc. N. Y. vol. i. p. 482. 



Mc Murtrie's Cuv. vol. ii. p. 285. 



Yarrell's British Fishes, vol. ii. p. 379 et fig. 



This species, which sometimes weighs 200 pounds, is called 

 by the fishermen " Thresher,''^ and '•' Sivingle tail,^^ from the 

 motions of its tail, which is often used with great force in de- 

 fence. It is met with in our waters in summer, not often 

 however, pursuing tnackerel and menhaden, upon which it 

 feeds. Generally it is taken in nets with other fish ; when 

 taken with the hook, it is secured with much difficulty on 

 account of the constant and powerful threshing of its tail. 



On the 28th of July 1838, I was fortunate enough to see a 

 very fine male* specimen of this shark, which was taken in 



* Both Pennant's and Yarrell's plates are evidently taken from female specimens. 



