128 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Figure 15. — Pelagic prejuvenile Pseudopriacanthus altus, 34.0 mm. standard length (CU 27831). 



8.2 mm., when small, very dark chromatophores 

 were evident over most of the head and body. At 

 10.2 mm. these chromatophores had darkened the 

 entire external surface. In addition, a series of 

 many sharply defined dark spots had appeared 

 on the future course of the lateral line. Above 

 this series was a second row of about 10 evenly 

 spaced, larger dots (these were still evident at 

 48.6 mm.; see fig. 17). No further changes in 

 body pigment occurred by 15.0 mm. except for 

 the reappearance of isolated dark spots in the 

 region of the cleithrum (fig. 12). This color 

 pattern persisted from about 20 to 30 mm., with 

 the exception of a lightening of the skin and scales 

 covering the bases of the caudal rays. At this 

 approximate size, dark chromatophores began to 

 outline the scales just anterior to their ctenii and 

 to cover the scale pockets (see fig. 15). By 58.9 

 mm., the dark chromatophores covered only the 

 pockets and gave the scales the appearance of 

 having dark centers (fig. 18). Suggestions of 

 three or four wide, poorly defined, incomplete 



vertical bars also appeared on the 34.0-mm. speci- 

 men illustrated in figure 15. These bars may 

 persist to adulthood and are especially noticeable 

 when the fish is alive. The chromatophores ap- 

 pearing over the center of those scales in the 

 regions of the bars were more expanded and in- 

 tense. This pigmentation persisted, especially 

 above the lateral line, to the largest specimens. 



Fin Pigmentation 



Pectoral fins. — Immaculate at all sizes. 



Pelvic fins. — All specimens up to 6.6 mm. had 

 immaculate pelvic fins (figs. 8-10). By 8.2 mm., 

 these fins had a scattering of small dark chromato 

 phores along the rays and onto the membranes 

 connecting them. These chronuitophores spread 

 and increased in number until the fins, with the 

 exception of their immaculate tips, were com- 

 pletely covered with dark pigment by 10.2 mm. 

 The tips also were covered by 15.0 mm. (fig. 12). 

 In specimens larger than 10.2 mm., the pigment 

 was progressively less intense on the rays than on 



