352 EIGHTH PACIFIC SCIENCE CONGRESS 



ic.ally lie somewhat between the Hawaiian and central Pacific faunal 

 areas, and a mixture of these two faunas (but with a high predom- 

 inance of Hawaiian forms) is found at Johnston. Nevertheless, no 

 intergradation between the Hawaiian endemics and their central Pacific 

 counterparts was found at Johnston. Among four species complexes 

 investigated in some detail (Muraenichthys cookei- laticaudata, Gymno- 

 thorax eurostus-buroensis, Acanthurus sandvicensis-triostegus and Kuhlia 

 sandvicensis), the Johnston populations of the first three represented 

 the pure Hawaiian stock, and of the fourth the pure central Pacific 

 form. In no instance were both the Hawaiian and the central Pacific 

 forms found at Johnston, nor have they been found together elsewhere. 



As to the harmonic nature of the Hawaiian fish fauna, a very high 

 proportion of the families and genera of shore fishes found in the central 

 Pacific east of Samoa have representatives in Hawaii. There are, how- 

 ever, two notable and curious gaps in the Hawaiian shallow-water fish 

 fauna. Throughout most of the tropical Pacific, two of the most prom- 

 inent genera are Lutjanus and Epinephelus. In the northernmost of the 

 Line Islands, for example, perhaps a half dozen species of each of these 

 genera occur. In the Hawaiian Islands and Johnston Lutjanus appears 

 to be totally unrepresented, and Epinephelus occurs only in a single, 

 deep-water form. Yet the families to which these two genera belong are 

 abundantly represented in Hawaii by other, smaller, deeper-water genera. 

 These gaps seem especially peculiar in that both genera are made up 

 of generalized, moderate to large sized fishes. Furthermore, both are 

 present in Japanese waters that would seem to be colder than those of 

 Hawaii. 



With regard to the relative size of the Hawaiian fish fauna, little 

 can definitely be said. On the one hand numerous central Pacific species 

 are unrepresented in Hawaii. On the other, more inshore species are 

 recorded from Hawaii than from any one central Pacific island group 

 east of Samoa. However, except for Hawaii, no central Pacific island 

 group east of Samoa has been adequately collected. Under any circum- 

 stances the Hawaiian inshore fish fauna, with some 400-500 known 

 species, cannot be called depauperate. 



Characteristics of Hawaiian Endemic Fishes 

 The characteristics by which Hawaiian endemic fishes differ from 

 their ancestral forms, i.e., their central Pacific representatives, can best 

 be treated under two categories: physiological and morphological. In 

 morphological features the Hawaiian endemic fishes show no pattern 

 of divergence from their central Pacific relatives. One Hawaiian en- 

 demic has a greater number of fin rays; a second has fewer gill rakers; 

 a third has the dorsal fin originating farther forward; a fourth has 



