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PACIFIC SCIENCE, Vol. XI, January, 1957 
males and also tend to have lunate caudal fins. 
More than likely an histological examination 
of the gonads of small " varius ' would show 
both sexes displaying the varius or juvenile color 
pattern. 
Marked sexual dimorphism, expressed as 
coloration differences, is not unusual among the 
labroid fishes. Longley (Longley and Hilde- 
brand, 1941. Papers from Tortugas Lab. 34: 
196-198) showed that in Thalassoma bifasciatum 
only adult males attain the bifasciatum color 
pattern, whereas females and young males ex- 
hibit a coloration so characteristic that they were 
long called T. nitidum. Recently Randall (1955. 
Copeia 3: 237) has demonstrated that Stethojulis 
renardi is merely the adult male of S. strigiventer, 
and Brock and Yamaguchi (1954. Copeia 2: 
154-155) have shown that Scarus ahula is the 
female of S. perspicillatus. The latter authors con- 
trast the bright blue, green, and yellow pattern 
of male perspicillatus with the rather drab pattern 
of the female, a situation quite similar to that 
obtaining in Gomphosus . 
One line of evidence which seems to cast 
doubt on our hypothesis that tricolor and varius 
are dimorphic forms of the same species is their 
pattern of distribution and relative abundance. 
In the 2 -to 35-foot depth range sampled for this 
study tricolor occurred mostly in deeper water 
and was uncommon even there. G. varius , on 
the other hand, seemed to be uniformly dis- 
tributed throughout this range and was com- 
mon to abundant. Every rotenone or sight- 
observation station yielding tricolor also pro- 
duced varius , but the reverse was certainly not 
true. Disjunctive distributions and aberrant sex 
ratios such as those found in this study do not 
necessarily indicate that varius and tricolor are 
separate species, particularly in view of Gosline 
and Strasburg’s recent work (1956. Copeia 1: 
9-18), on the even more markedly dimorphic 
Hawaiian moringuid eels. 
The name to be applied to our Gomphosus 
cannot be verified at this time. Gomphosus varius 
Lacepede (1802. Hist. Nat. Poiss. 3:100, 104) 
predates G. tricolor Quoy and Gaimard (1824. 
Voyage Uranie, Zook: 280), the type localities 
being Tahiti and the Hawaiian Islands re- 
spectively. We accordingly refer our material to 
varius , but with the following reservation. In the 
Indian Ocean the central Pacific forms of Gom- 
phosus are replaced by two or three other species, 
one or two of which may be identical with the 
Pacific varius. Based on our experience it would 
appear that sexual dimorphism is also present 
in the Indian Ocean Gomphosus , and that males 
may occur as either the blue-green tricolor form 
or as a violet-blue species called coeruleus. The 
precise relationship of the Indian Ocean to the 
Pacific Gomphosus remains to be demonstrated. 
When this is done it may be that what we here 
call varius will be synonymized with coeruleus. 
Donald W. Strasburg 
U. S. Fish and Wildlife Service, Honolulu 
and 
Robert W. Hiatt 
Department of Zoology and Entomology 
University of Hawaii, Honolulu 
