438 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



grating posteriorly from the integument over the 

 hypural bone. 



A l7.5-mm. specimen showed light tan pigmen- 

 tation diffused throughout the area that was clear 

 in the 9-mm. specimens (that section below the 

 lateral midline and above the anal fin). ,A few 

 pigment spots were evident on both dorsal fins, 

 and pigment had spread to about midway of the 

 caudal fin. 



In a 23.0-mm. specimen, pigmentation in the 

 thoracic region appeared to be spreading from the 

 large chromatophores seen in the smaller speci- 

 mens. Just below the dorsal fins a second row of 

 pigment spots was present above the row of 

 chromatophores along the lateral midline. Anal, 

 pelvic, and pectoral fins were still unpigmented. 

 The chromatophores of the principal rays of the 

 caudal fin had extended along the edges of the 

 rays for about three-quarters their length. 



In a 33.6-mm specimen, the pigmentation of the 

 first dorsal fin had spread across the interspinous 

 membranes to form a stripe about two-thirds of 

 the distance from the base of the fin to the tips of 

 the spines. The pigment spots about midway be- 

 tween this stripe and the base of the fin were 

 grouped to indicate the formation of a second 

 stripe. Other pigmentation remained the same. 



Ina45.8-mm. formal in- preserved specimen (fig. 

 25, lower specimen), the second stripe of the first 

 dorsal fin was complete across the interspinous 

 membranes. In the distal one-third of the second 

 dorsal fin there was a pigmented area on each ray 

 just below a similarly pigmented area on the pre- 

 ceding ray. This gave the impression of a postero- 

 ventrally directed, oblique black stripe. A similar 

 stripe, but extending through only the first four 

 rays, was forming near the base of the fin. 



The 47.2-mm. metamorphosed juvenile (fig. 25, 

 upper specimen) had a uniform light tan back- 

 ground. The lower half of the body was clear of 

 chromatophores except for tiny scattered pigment 

 spots. The upper half retained some large pig- 

 ment spots, and the scales had pigment on their 

 margins. A third stripe had made its appearance 

 on the second dorsal fin. 



The 78.0-mm. specimen (fig. 27), preserved in 

 isopropyl alcohol, was virtually devoid of scales 

 and was tan throughout. Tliere were no pigment 

 spots in the body except for a few minute ones 

 along the dorsal surface. This specimen was one 



of the few M. auratus I examined that retained 

 pigmentation of the caudal fins. Pigment spots 

 were grouped along the principal rays to form four 

 bars in the upper lobe and five in the lower. 



The following notes on the color of an adult 

 M. auratus were taken from a specimen which had 

 been in formalin for 13 days : 



Head red. Sides red above the lateral mid- 

 line, shading to a silvery abdomen. Bright red 

 stripe along midline, below which are two yellow 

 stripes. Pectorals i^ink with four faint stripes 

 (color not recorded). Pelvics clear with four 

 yellow stripes. Anal yellow. First dorsal clear 

 with two stripes, upper bright orange, lower 

 yellow. Second dorsal clear with four stripes, 

 yellow flecked with black. Dorsal half of 

 caudal with seven or eight faint bars, some 

 bright red, some orange, and some yellow. 

 Ventral half of caudal with faint bars, the num- 

 ber indeterminate (color not recorded). 

 Specimens that had been in preservative for a 

 considerable length of time were a pale yellow 

 throughout and had lost all distinctive markings. 



Fins 



Spinous dorsal. — With one exception all of the 

 specimens examined had eight spines in the first 

 dorsal fin, including the small first spine (fig. 28). 

 One specimen had seven spines including the small 

 first spine. 



Figure 28. — Spinous dorsal fin of 44.9-mm. Mnlliis 

 auratus. Line equals 2 mm. 



Soft dorsal. — The adult complement is one un- 

 branched ray plus eight branched rays. 



At 11.9 mm. there was no segmentation, but 

 the last eight rays were segmented on a 14.5-mm. 

 specimen. The first ray did not usually segment 

 before 47 mm. 



The last ray was branched at 9 mm. Additional 

 branching did not occur until 18 mm.; it was 

 complete at 40 mm. 



Pectoral. — All of the specimens examined 

 showed an adult complement of 15 to 17 fin rays 



