HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 167 



one and a half times length of first, wider posteriorly than anteriorly 

 but tapering along posterior margins to narrow, terminal, anal region. 



Abdomen of immature female one-segmented, slightly larger than 

 second abdominal segment of male. Anterior surface slightly nar- 

 rower than posterior, lateral margins broadly convex. 



Antennule of male and immature female two-segmented, excluding 

 frontal plate, attached to ventral sm*face of frontal region under free 

 surface of lunule. First segment one and one-fourth times length of 

 second; wider in middle than at either end. Proximal portion of an- 

 terior margin curving concavely outwards to widest point then con- 

 vexly to narrow distal surface. Distal half of anterior margin with 

 about 22 plumose setae. Second segment club-shaped, with naked 

 seta on distal portion of posterior margin, 15 naked setae from 

 rounded distal surface (fig. 8/). 



Second antenna of male three-segmented, attached medially and 

 slightly posterior to antennule. Fh'st segment long, length equal to 

 that of second segment; broader proximally than distally, attached 

 to cephalothorax along most of inner surface. Distal end of first 

 segment uTegularly concave, forming articular surface for second 

 segment. Second segment well developed, proximal two-thirds of 

 inner margin broadly convex, with small, slightly protruding adhesion 

 pad just proximal to inner distal surface and small, acuminate pro- 

 jection on posterior distal surface. Distal surface of second segment 

 irregular, with several articular surfaces not appearing heavily chitin- 

 ized. Third segment and processes small, less than half length of 

 second segment. Terminal process projecting slightly past region of 

 third segment attachment, forming minute, bifid, sharply pointed 

 structure (fig. 8^). 



Second antenna of immature female three-segmented, much more 

 weakly developed than that of male. First segment (not shown in 

 figure) short, forming articular surface for second segment, with small, 

 spinelike process projecting posteriorly from posterior margin. Sec- 

 ond segment slightly broader proximally than distally, with small, 

 lobate projection from proximal region of posterior surface and small, 

 lappet-like structure from middle of distal region of posterior surface. 

 Third segment and terminal process forming acuminate, spinelike 

 structure ; division between segment and process not visible ; terminal 

 process curving sharply inwards distally (fig. 8h). 



Mandible of male and immature female four-parted. First part 

 broader proximally than distally, with even taper to junction of second 

 part. Second part short, about half length of first part, tapering 

 sharply to junction with third part. Third part elongate, slightly 

 swollen distally, at junction with fourth part. Fourth part short, 

 slightly more than half length of third part, curved inward; outer 



