HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 



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on first segment with indistinct frilled membrane around base, frilled 

 membrane around base of second segment spine distinct. Third 

 segment with tliree spines on distal surface, all with distinct frilled 

 membrane around base. Innermost spine longest, outer two of 

 approximately equal length, inner margins of all three spines lightly 

 setuliferous (fig. Id). 



The character of the membranes, spines, and setae on the thoracic 

 legs is given below. Except for minor variations such as the length 

 and spacing of the setae, the thoracic legs of C. constrictus and C. 

 randalli are identical. Because of this there is no comparison of these 

 appendages in the two species. (For explanation of symbols, see 

 figure 1.) 



Width of caudal rami about equal to length, with six plumose 

 setae ; two long setae from middle of distal surface and two each from 

 inner and outer distal surfaces. Inner margin setuliferous. Caudal 

 rami arising from distal ventral surface of abdomen (fig. 6g — one of 

 inner setae not visible). 



Remarks.^ — ^The differences between C. randalli and its closest 

 relative, C. constrictus Heller, are given in the general description of 

 C. randalli. C. constrictus was not taken from Hawaiian acanthurid 

 fishes, nor has it been taken from other fishes that have been collected 

 from this area. C. constrictus has been described from the west coast 

 of Central and North America, and the author has collected specimens 

 (to be published) on fishes of Eniwetok atoll. These two species 

 appear closely related morphologically although there are some dis- 

 tinct differences between them. The major differences are the length 

 of the abdomen and the shape and length of the fourth thoracic leg- 

 bearing segment. The abdomen of C. randalli is one and a half times 

 the length of the abdomen of C. constrictus; the fourth thoracic leg- 

 bearing segment of C. constrictus is 1.3 times that of C. randalli and 

 does not possess the platelike structure present on the dorsal surface 



