59 



species, which agrees perfectly well in every other particular with cyanos- 

 tigma. The specimens, as may be seen, are quite small, and the spines 

 have more of the appearance of excrescences than of permanent arma- 

 tures. 



SICYOPTERUS STIMPSONI, {Gill) Bleek. [No. 17991]. 



Sicydium {Sicyojyterus) stimpsoni, Gill, Proc. Acad. Nat. Sci. Phila., 1860, 101. 

 Sicydium stimpsoni, Gunther, Cat. Fish., iii, 1861, 93. 

 Sicyopterus stimpsoni, Bleeker, Arch. Neerland., ix, 1874, 313. 



Locality : Fresh-water streams of Oahu. 



AWAOUS ORASSILABRIS, [Gthr.) Streets [Nos. 17974, 17996J. 



GoMus crassilahris, Gui\THER, Cat. Fish., iii, 1861, 63. 



Locality: Fresh-water streams of Oahu. 



There is a marked difference between the sexes of this species, as 

 there is probably in other species of Gobiidce. Professor Gill first sug- 

 gested to us this probable difference, and our dissections confirmed his 

 suggestion. 



In the males the anal papilla is triangular, with a prolonged and 

 slender apex; while in the females It is short, broadly quadrilateral, and 

 the free margin fringed, and sometimes emarginate. The difference ex- 

 tends to the head also. In males it is broad, rounded in front, and the 

 upper profile of the snout is slightly inclined downward, as in the typi- 

 cal Gobius; the lips are thick, and the end of the superior maxillary bone 

 extends to or beyond the vertical from the center of the eye. The head 

 of a female is narrower, more pointed in front, the lips less turned, and 

 the end of the upper maxillary is anterior to the vertical from the center 

 of the eye. In one specimen, a young male, we failed to find any evi- 

 dence of testicles. In this the anal papilla was similar to" those of the 

 other male specimens, while the general features of the head were those 

 of a female. In Giinther's description these differences are for the most 

 part confounded, and it would be impossible to identify the species from 

 one sex only, but if both are at hand they conform to it in every par- 

 ticular. 



