218 U.S. NATIONAL IVnJSEUM BULLETIN 202 Vol. 2 



HEMIGYMNUS FASCIATUS (Bloch) 



Plate 101, D 



Labrus fasciatus Bloch, Naturgeschichte der auslandischen Fische, vol. 6, p. 

 6, pi. 290, 1792 (type locality, Japan). 



SPECIMENS STUDIED 

 Bikini Atoll. 4 stations, 5 specimens, 75 to 151 mm. in standard length. 1 lot, 

 Univ. Washington, 2 specimens, 52 to 146 mm. 



Description. — Head 2.5 to 2.7; greatest depth 2.4 to 2.5; longest 

 pectoral ray 4.4 to 4.7; snout tip to anus 1.7; snout to dorsal origin 

 2.3 to 2.4; all in standard length. Snout 2.1 to 2.4; eye 4.5 to 6.5; 

 postorbital length of head 2.1 to 2.2; interorbital space 3.9 to 4.1; 

 longest pectoral ray 1.6 to 1.7; least depth of body 2.0 to 2.1; all in 

 length of head. Eye in fleshy interorbital space 1.4 to 1.9. 



Dorsal profile of head forming an angle of about 65 to 70 degrees 

 with the ventral contour of head; pectoral fin reaches to opposite 

 about ninth or tenth lateral line pore; second soft pelvic ray longest, 

 reaching to or nearly to anus; distal margin of caudal fin a little 

 rounded. 



Color in alcohol. — Background coloration of body blackish, with 4 

 white bars, the first from between bases of dorsal spines IV and V, 

 continuing behind pectoral base and meeting its fellow halfway be- 

 tween pectoral base and anus ; second from base of first soft dorsal ray 

 to anus ; third from between bases of soft dorsal rays 5 and 6 to middle 

 of length of anal fin base; and fourth, usually very faint, just behind 

 rear end of bases of dorsal and anal fins across caudal peduncle ; head 

 and breast in front of pelvic and pectoral bases whitish ; a dusky spot 

 behind eye; base of pectoral fin black, the fin hyaline; pelvic and anal 

 fins black; dorsal and caudal fins dark brown; usually a few black 

 spots posteriorly on body, one near midbase of caudal fin and one 

 (about 3 scale rows in front of it) on caudal peduncle are constant; 

 side of head with lengthwise streaks below eye. The young speci- 

 men, 52 mm. long, has 6 narrow vertical white bars, and several 

 white streaks radiating from eye, some meeting on ventral line under 

 head; body and head blackish. 



Ecology. — This species was seldom seen or taken on the reefs or in 

 deeper water. 



Remarks. — Specimens in the U. S. National Museum indicate that 

 one or more races or subspecies may be included under the name 

 fasciatus, but sufficient material on which to base definite conclusions 

 is not available at this time. Differences are noted in regard to color 

 pattern; specimens from the Marshall, Philippine, and Samoan 

 Islands have much narrower white bars than those from Japan and 

 Okinawa, a condition that needs further study. 



