272 BULLETIN 10 0, UNITED STATES NATIONAL MUSEUM 



Genus HETEROSCYMNUS Tanaka 



Heteroscynmus Tanaka, Fishes of Japan, vol. 6, p. 102, 1912. (Type, Hetero- 

 scymnus longus Tanaka, monotypic.) 



Body elongated, somewhat compressed, body cavity % total 

 length. Tail short. Head depressed. Snout pointed. Eyes small, 

 without nictitating membrane. Mouth nearly transverse, with deep 

 groove at each angle. Teeth unlike in two jaws, upper lanceolate and 

 numerous, lower larger, compressed with oblique triangular cusp. 

 Nostrils near snout end. Gill openings moderate, before pectoral. 

 Spiracle small, behind and elevated from eye. Scales minute. Fins 

 rather small. Dorsals spineless, first above postpectoral space. No 

 anal. Caudal short, deep, without pits. 



Japan. 



HETEROSCYMNUS LONGUS Tanaka 



Heteroscymnus longus Tanaka, Fishes of Japan, vol. 6, p. 102, pi. 26, figs. 

 102-107, 1912 (type locality: Tokyo market, Japan). — Garman, Mem. Mus. 

 Comp. Zool., vol. 36, p. 239, 1913 (Sagami Sea ) .—Fowler, Proc. 4th (1929) 

 Pacific Sci. Congr., Java, p. 497, 1930 (reference). 



Depth to subcaudal 4% ; head 514? width 1%. Snout 2% in head, 

 obtuse as seen above; eye 8, 3 in snout, 4I/2 in interorbital ; mouth 

 width 2^4 in head, little arched, with groove from angle backward 

 little less than i/^ to gill opening; similar but very short groove on 

 upper lip; lips thin; upper teeth lanceolate, sharp, irregular, close 

 set, in several rows, of which 4 visible from outside and 20 in row 

 visible from • outside ; lower teeth much larger, triangular, directed 

 somewhat outward, without serration in margin, arranged in 2 rows, 

 about 15 in row visible from outside, actual number 18; preoral 

 length £1/^ in head; interorbital l%o; convex. Gill openings sub- 

 equal, last before pectoral base, largest about twice eye. Spiracle 

 small, oval, behind eye, interspiracle space 2% in head. 



Scales minute, finely shagreened, none enlarged. Short and rather 

 indistinct ridge below lateral line on caudal peduncle. 



First dorsal origin slightly nearer snout tip than subcaudal origin, 

 front fin edge 1% in head ; second dorsal origin close behind ventral 

 base, front fin edge 2i/^ in head ; least depth of caudal peduncle 4 in 

 head; caudal length from subcaudal origin Zy^ in rest of body, sub- 

 caudal 1% in caudal length; pectoral I14 in head, width 1% its 

 length ; ventral length 1% in head. 



Blackish brown, edges of all fins darker. Length, 1,360 mm. 

 (Tanaka.) 



Japan. 



