HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 181 



Fourth thoracic leg-bearing segment of female and male short, 

 lateral regions drawn out in region of fourth leg attachment so that 

 middle of segment wider than either end. Terminal portion of lateral 

 extension cup-shaped, forming socket-like attachment for fourth 

 thoracic legs. Division between fourth thoracic leg-bearing segment 

 and genital segment distinct. 



Shape of female genital segment variable, dependent upon number 

 of eggs in segment. Segment flaccid and ovoid, surrounded by loose 

 membrane, in females that recently have extruded egg strings; almost 

 circular in females in which genital segment packed with eggs (figs. 

 116,^). Fifth legs seen ventrally as lobelike projections from pos- 

 terior ventral surface of genital segment, just lateral to nodelike 

 projection of posterior surface, bearing three plumose setae; additional 

 plumose seta present sHghtly lateral and anterior to first three (figs. 

 llb,e,g). 



Genital segment of male ovoid, width about three-fourths length. 

 Fifth and sixth legs distinctly visible protruding from segment. Fifth 

 legs small, lappet-like, bearing single, short, plumose seta from base 

 and two plumose setae from distal end, inner seta almost twice length 

 of outer. Sixth legs also lappet-like, more distinct than fifth legs; 

 lappet-like structure with three plumose setae from distal surface 



(fig. 11/). 



Abdomen of female short, less than one-third length of genital seg- 

 ment. Both Wilson (1905) and Shiino (1959) indicate that the abdo- 

 men arises from the ventral surface of the genital segment. The point 

 of attachment, however, appears to depend on the size of the genital 

 segment. In females with an empty genital segment the abdomen 

 joins to the ventral surface; in those with the genital segment full of 

 eggs the abdomen attaches to the middle (in lateral view) of the 

 posterior surface of the segment. 



Abdomen of male similar to that of female though width slightly 

 less than that of female abdomen. Junction of genital segment and 

 abdomen on posterior ventral surface of genital segment. 



Length of egg strings variable, containing 10-30 eggs with average 

 of 15. Number of eggs in egg strings of each specimen usually equal, 

 differing by not more than two. 



Antennule of female two-segmented, excluding frontal plate, at- 

 tached to frontal region near posterior lateral margin, lateral edge of 

 frontal region overlapping first segment slightly. First segment 

 about two times length of second, wider in proximal region than in 

 distal, with small, bifm-cate protrusion on posterior distal corner. 

 Fii'st segment with 20 plumose setae on anterior surface. Width of 

 second segment slightly less in proximal than in middle and distal 



