226 BULLETIN 10 0, UNITED STATES NATIONAL MUSEUM 



2 jaws; upper awl-shaped, raptorial; lower compressed, smooth on 

 edges, sectorial, more or less oblique. Nostrils below snout, oblique, 

 well advanced. Spiracles large, behind eyes, elevated. Two small 

 dorsals, with spine shortly exposed. Caudal well developed, verte- 

 bral axis raised backward, subcaudal lobe rather weak. 



Small sharks, usually of deep water. The dorsal spines are often 

 weak or poorly developed. Zameus based primarily on scale struc- 

 ture is not distinct from Scymnodon. Garman includes Gentro- 

 scymnus macracanihus Regan from Magellan Straits, placing it 

 near Scymnodon plunketi, though its well developed dorsal spines 

 strongly projecting. 



ANALYSIS OF SPECIES 



o' Second dorsal origin behind ventral origin ; pectoral not reaching second 

 dorsal origin. 

 &\ Zameus. Orbit more than half snout. 

 c\ First dorsal origin nearly midway between hind orbital angle and second 

 dorsal origin or nearly midway between snout tip and hind end of 



second dorsal ; second dorsal and ventral subequal squamulosus 



cl First dorsal origin midway between last gill opening and second dorsal 

 origin or midway between snout tip and end of last caudal vertebra. 



sherwoodi 

 6'. Scymnodon. Orbit less than half of snout; first dorsal origin slightly 

 nearer first gill opening than second dorsiil origin (east Atlantic)- ringens 

 a*. PROscYMNODfON. Second dorsal origin above or close behind ventral ori- 

 gin, fin greatly larger than ventrals ; pectoral nearly reaches opposite first 

 dorsal origin which at first third in total length ; orbit nearly long as snout. 



plunketi 

 Sub genus Zameus Jordan and Fowler 



SCYMNODON SQUAMULOSUS (GUnther) 



Centrophorus squamulosus Gunthek, Ann. Mag. Nat. Hist., ser. 4, vol. 20, p. 433, 

 1877 (type locality: Off Inosima, Japan); Rep. Voy. Challenger, vol. 22, 

 p. 5, pi. 2, fig. B, 1887 (lat. 35° 11' N., long. 139° 28' E., in 345 fathoms).— 

 Jordan and Snyder, Annot. Zool. Japon., vol. 3, pp. 41, 129, 1901 (Enoshima). 



Zameus squamulosus Jordan and Fowler, Proc. U. S. Nat. Mus., vol. 26, p. 633, 

 1903 (compiled). 



Scymnodon squamulosus Regan, Ann. Mag. Nat. Hist., ser. 8, vol. 2, p. 48, 1908 

 (Atlantic coasts Europe). — Gabman, Mem. Mus. Comp. Zool., vol. 36, p. 209, 

 1913 (Japan).— Fowler, Proc. 4th (1929) Pacific Sci. Congr., Java, p. 496, 

 1930 (references). — Schmidt, Trans. Pacific Comm. Acad. Sci. U. S. S. R., 

 vol. 11, p. 7, 1931 (Misaki; Sagami Bay). 



Depth 5% to subcaudal origin; head 41/2, width about 21/5. Snout 

 334 in head; orbit 51/^, 11/2 in snout, about 2% in interorbital ; mouth 

 width about 2% in head, rather long deep groove at each angle, upper 

 labial fold about half jaw length, lower % jaw length; upper lip 

 with fringed edge ; teeth entire, upper narrower and more erect, lower 

 broader with triangular cusp on subquadrangular base ; nostrils mid- 



