Fishes of Massachusetts. 529 
ORDER II. 
CHONDROPTERYGII BRANCHIIS FIXIS. 
Famity I. 
SELACHII. 
CARCHARIAS. Cuv. 
Generic characters. Jaws and head depressed; 
nostrils pierced in front; teeth pointed and cutting, 
often serrated at the edges; first dorsal fin large 
and placed behind the pectorals and before the 
ventrals ; pectoral fins large. : 
C. vulpes. Lin. The For Shark. Thresher. 
Turton’s Linneus, vol. i. p. 918. db d 
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 260 
pounds, is called by the fishermen “ Thresher,” and 
“ Swingle tail,” from the motions of its tail, which 
is often used with great force. in defence. It is met 
with in our waters in summer, not often however, 
pursuing mackerel and menhaden, upon which it 
VOL. II.—NO. III—IV. 49 
