Storer’s Synopsis of the Fishes of North America. 505 
GENUS III. ALOPIAS, Bonar. 
Head, dorsal and anal fins, and spiracles, as in the genus Lamna; upper 
lobe of the tail very long, with a depression at the base. Teeth triangular, 
flat, with smooth cutting edges in both jaws, curving outwards .on each side 
from the centre. Branchial openings small, the last over the pectoral fins. 
1. Alopias vulpes, GmEx. 
Body fusiform. The upper lobe of the tail nearly as long as the body. Teeth trian- 
gular, pointed, smooth upon their edges. A dark bluish lead-color above ; beneath white, 
with light bluish blotches upon the outer edges of the abdomen. 
D. (2). P.@). V.@)- Ast)! €:(@. Length, 12 to15 feet. 
Massachusetts, Srorer. New York, Mircuiuy, Decay. 
Squalus vulpes, Gwet., Lry., Syst. Nat., 1. pt. 3, p. 1496. 
Long-tailed Shark, Pennant’s Brit. Zool., mr. p. 110, pl. 14. 
Squalus vulpes, Fox-Shark, Suaw’s Gen. Zodl., v. p. 333, 
Thresher, Mrrcuizt, Medical Repository, vit. p. 77. 
Squalus vulpes, Thresher or Long-tailed Shark, Mrrcuitt, Trans. Lit. and Phil. Soc. of N. Y., 1. p. 482. 
Carcharias vulpes, Fox-Shark or Thresher, GrirrirH’s Cuy., x. p. 599. 
Squalus vulpes, Sea-Fox or Thresher, Jenyns’s Brit. Vert., p. 498. 
Carcharias yulpes, Fox-Shark or Thresher, StoreR’s Report, p. 182. 
Alopias vulpes, Sea-Fox, Thresher, Sea-Ape, YARRELL’s Brit. Fishes (2d edit.), 1. p. 523, fig. 
Carcharias vulpes, Thresher or Fox-Shark, Linstrey’s Cat. Fishes of Connecticut, 
fe bs Thresher Shark, DExay’s Report, p. 348, pl. 61, fig. 199. 
GENUS IV. MUSTELUS, Cuv. 
Teeth blunt, forming a closely compacted pavement in each jaw ; with tem- 
poral orifices. First dorsal in advance of the ventrals. Lower lobe of the 
caudal short. No spines. 
1. Mustelus canis, Mrrcnitt. 
Body cylindrical, tapering, elongated. Back and sides of a uniform slate-color ; abdo- 
men a dusky white. Body rough, when the finger is passed towards the head. Head flat 
between the eyes. 
D. (2). P. (?). V.(@). A. (2). ©. (2). Length, 2 to 4 feet. 
Massachusetts, Srorer. New York, Mircuinn, Decay. 
Called ‘* Dog-fish Shark,’’ by the fishermen of Massachusetts Bay. 
Squalus canis, Dog-fish, Mircninz, Trans. Lit. and Phil. Soc. of N. Y., 1. 486, pl. 64, fig. 209. 
Mustelus canis, American Hound-fish, DEKay’s Report, p. 355, pl. 64, fig. 209. 
GENUS V. SELACHUS, Cvv. 
Two dorsal fins, the first placed but little behind the line of the pectorals, 
