NOTES ON PHALLOSTETHID FISHES MYERS 139 



Genus NEOSTETHUS Regan 



NEOSTETHUS LANKESTERI Regan 



This species is known only from the types. 



NEOSTETHUS AMARICOLA (ViUadolid and Manacop) 



GulaphaUus amaricoJa Viixadolid and Manacop, 1934, p. 194, pi. 1 (Pasay, 

 Rizal Province, on Manila Bay, Luzon; in brackish sloughs). 



This species has only recently been described, although it was 

 mentioned several years ago (Mj-ers, 1928, p. 11). The U. S. S. 

 Albatross obtained what I take to be this form at several localities 

 in Luzon and Leyte, all apparently brackish-water habitats. There 

 are three males from a fish pond at San Antonio, Cavite, Manila 

 Bay (U.S.N.M. no. 98833) ; two males from the mouth of the Palani 

 River, Port San Vicente, at the northern end of Luzon (U.S.N.M. 

 no. 98834) ; six immature specimens from the Ragay River, Ragay 

 Gulf, on the south coast of Luzon (U.S.N.M. no. 98835) ; and one 

 male and three females from brackish water in the river at Port 

 Dupon, Leyte (U.S.N.M. nos. 9883G and 98837). 



This species is very close to N. lankesferi, differing chiefly in the 

 presence of two (instead of one) rays in the first dorsal fin and 

 slightly but sharply in the structure of the priapium in the region 

 of the infrasulcar prominence. N. lankesterl has two projections in 

 this region, the seminal papilla and the infrasulcar prominence; 

 N. amaricoJa appears to have but one, which ViUadolid and Manacop 

 call a "penislike structure." This bears one short spine, which they 

 identify as a second ctenactinium. I am inclined to doubt this 

 identification; very likely this small spine is the homologue of the 

 papillary bone that supports the seminal papilla in N. lankesterl. At 

 any rate, this sharp external spine serves to distinguish N. amarlcola 

 immediately from its close relative. 



NEOSTETHUS SIAMENSIS. new species 



Eolotype.—\J.^.'^M. no. 102140, a female 28.7 mm in standard 

 length, collected in the estuary of the Chantabun River, south- 

 eastern Siam, in April 1933, by Dr. Hugh M. Smith. 



Before his return from Siam, Dr. Smith sent me this single female 

 as a phallostethid of a type entirely new to him. Only this one 

 specimen was obtained. While in most cases it is not possible to 

 determine the genus of fishes of this family without male specimens, 

 the general habitus of this example makes me think it is probably 

 closely related to NeostetJms^ even if it is not a member of that 

 genus. The compressed, deep body distinguishes it immediately 

 from the specimens of N. aniaricola recorded above. Judging from 



