160 



FISHERY BULLETIN OF THE FISH AND "WILDLIFE SERVICE 



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10 



20 



40 60 



STANDARD LENGTH IN MM. 



Figure 32. — Relation of eye diameter to standard length. Dots represent study specimens; x's, Beebe's specimens; 

 circles, Voss's specimens; triangles, Baughman's specimens; and large black dots, the unidentified species. 



caudal fin, witli increasing density, at appro.xi- 

 mately 10 mm. The preopercle and opprcle are 

 less densely pigmented than the dorsal part of 

 the snout or body at any particular size. At the 

 6-mm. size, scattered melanophores appear in the 

 pattern of chromatophores over the dorsal surface 

 of the body. In specimens smaller than 10 mm., 

 the dorsal surface of the brain case is pigmented 

 by scattered melanophores. 



In specimens exceeding 10 mm., the pigmenta- 

 tion changes little except for a gradual increase 

 in density. Generally it is as follows: Upper jaw 

 and sides of head, blue-black; mandible, non- 

 pigmented; eye, silver with black pupil; upper 

 body, dark blue to black; and lower sides of body 

 anterior to the anus and caudal, blue. The belly 

 is a silvery white, fins are usually ti-anslucent 

 (except for the dorsal), and spines are nonpig- 

 mented. Pigmentation on the dorsal fin develops 

 from a scattering of chromatophores on the lower 

 central portion at approximately 10 mm. to 



generally dense areas (with scattered less dense 

 areas) at approximately 20 mm. Tips of dorsal 

 fin rays are nonpigmented, and pigment on the 

 dorsal fin extends posteriorly to approximately 

 the 35th ray. Bars (or blotches) of chromato- 

 phores appear on the body at approximately 35 

 mm. and persist through the size range of speci- 

 mens examined. 



Color notes on fresh specimens (15-20 mm. in 

 standard length) are as follows: Dorsal surface 

 of head and body, steel-blue; sides of head and 

 upper opercles, blue-black; eye, silver-wliite with a 

 blue tinge and black pupil; ventral sides of body 

 from anus posterior, blue; anal and pectoral fins, 

 hyaline; caudal fin, translucent white; dorsal fin 

 anterior portion generally blue-black with yellow 

 and white streaks on rays, and posterior portion, 

 hyaline; and ventral fins are tinged with yellow. 



The principal variations from this pattern of 

 development in the unidentified species are as 

 follows: (1) In general, the pigment on the dorsal 



