PISHES OF NEAA^ YORK 23 



6 Mustelus canis (Mitchill) 

 Dog ^Imrh; Smooth Dogfish 



^qualus canis Mitchill, Trans. Lit. & Phil. Soc. N. Y. I, -486, 1815. 



Mustelus canis De Kay, N. Y. Fauna, Fishes, 355, pi. 64, fig. 209, 1842; 

 Storee, Hist. Fish. Mass. 251, pi. XXXYII, fig. 2, 2a, 1867; Jordan 

 & Gilbert, Bull. 16, U. S. Nat. Mus. 20, 1883; Jordan & Evermann, 

 Bull. 47, U. S. Nat. Mus. 29, 1896. 



Body cylindric, elongate, tapering greatly from the dorsal fin 

 to the tail; head flattened above, one fourth of total length 

 without caudal; snout obtusely pointed, one third as long as the 

 head. Hight of body equals one half length of head. Nostrils 

 large, semilunar, midway between tip of snout and angle of 

 mouth. Eye two fifths as long as the snout. Teeth in about 

 10 rows, smooth, flattened, the posterior edges of each tooth 

 slightly elevated. Spiracles small, circular, near the lower 

 posterior angle of the eye. Gill openings moderate, half length 

 of snout, the last two over the base of the pectorals. Hight of 

 dorsal fin, measured from middle of its base, slightly greater 

 than depth of body. Length of pectoral equal to base of dorsal. 

 End of ventral base midway between tip of snout and tip of 

 caudal, the length of the fin scarcely one third length of head. 

 Caudal fin as long as the head, its lower lobe short, blunt, about 

 one third as long as the upper. Color ashen gray above, some- 

 times with pale spots, white bejieath; outer edges of the dorsals 

 and anal with a black margin, specially in young; iris greenish 

 yellow. Length 3 feet. 



This is known as the dogshark, smooth dogfish and hound- 

 fish. It is extremely common in the north Atlantic and is a 

 source of great annoyance to anglers. The shark is not eaten 

 but it is used in making fertilizers and oil is prepared from its 

 liver. It occurs in Gravesend bay in August, September and 

 October. In captivity it is restless and delicate, often coming 

 to the surface of the water and struggling as if trying to escape. 

 Its food consists of small crustaceans, seaweed, etc. 



Genus galeocerdo Mtiller & Henle 



Body cylindric, elongate, tapering; mouth crescentic; teeth in 

 t)oth jaws large, oblique, coarsely serrate on both margins; 



