HISTORY OF THE FISHES OF MASSACHUSETTS. 241 



ORDER II. PLAGIOSTOMI. 



Gills fixed by their external edges, with five small external openings on each side. 

 No opercle. Jaws represented by the palatine and postmandibulary bones, which alone 

 are armed with teeth. Pectorals and ventrals always present, — the latter, in the male, 

 furnished on their internal margins with long appendages. 



FAMILY XXVIII. SQUALIDJB. 



Body elongated, cylindrical. Tail thick and muscular. Eyes lateral. Branchial open- 

 ings on each side, never underneath. 



GENUS I. CARCHARIAS. Cuv. 



One anal and two dorsal fins ; the first dorsal placed over the space between the pec- 

 toral and abdominal fins. Jaws and head depressed. Teeth flat, pointed, and cutting ; 

 serrated in the upper jaw, sometimes in both jaws. No temporal orifices in adults, but 

 rudiments may be observed in the foetus of some of the species. 



Carcharias griseus, Ayres. 



Tlie Gray Shark. 



(Plate XXXVI. Fig. 1.) 



Carcharias griseus, Ayres, Bost. Journ. Nat. Hist., iv. p. 293, pi. 12, fig. 4. 

 " " Storer, Synopsis. 



Color. The anterior and upper parts of the body are of a dark ash color ; sides light- 

 er ; beneath white. 



Description. Body much more elongated than that of the Lamna punctata; its 

 greatest depth, across from the origin of the dorsal fin, is equal to about one fifth the 

 entire length of the fish. The length of the head is equal to about one seventh the 

 entire length. The eyes are horizontally oblong, — their longest diameter one inch and 

 a half; the distance between the eyes is three and a half inches. The nostrils are large, 

 situated half way between the eyes and the tip of the snout ; similar in form to those of 



vol. ix. 39 



