HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 157 



thorax, including frontal region, 1.84 mm.; greatest width, excluding 

 marginal flange, 1 .84 mm. Greatest length of fourth thoracic leg-bear- 

 ing segment 0.29 mm.; greatest width 0.70 mm. Greatest length of 

 genital segment 1.23 mm.; greatest width 1.03 mm. Greatest length 

 of abdomen, excluding caudal rami, 0.90 mm. Length of egg strings 

 1.47 mm.; egg strings with about 28 eggs. 



Because of the similarity of the holotype specimen to specimens of 

 Caligus constrictus Heller, measurements were taken for comparative 

 purposes from an ovigerous female specimen of C. constrictus contained 

 in the collections of the U.S. National Museum and identified by C. B. 

 Wilson: Length from anterior end of frontal plate to posterior end of 

 caudal rami, excluding setae, 4.69 mm. Greatest length of cephalo- 

 thorax 1.23 mm.; greatest width, excluding marginal flange, 1.93 mm. 

 Greatest length of fourth thoracic leg-bearing segment 0.37 mm.; 

 greatest width of fourth thoracic leg-bearing segment 0.53 mm. Great- 

 est length of genital segment 1.84 mm.; greatest width 1.10 mm. 

 Greatest length of abdomen, excuding caudal rami, 0.62 mm. Length 

 of egg strings 2.34 mm. Egg strings with about 45 eggs apiece. 



Description. — Holotype specimen light brown in alcohol, no evi- 

 dence of pigment pattern; eyes light red. 



Cephalothorax ovoid, greatest width in middle of body; frontal 

 region narrow, division between region and cephalothorax indistinct. 

 Lunules small, projecting slightly from anterior margin of frontal 

 region (fig. 6e). Lateral margins of cephalothorax irregular, with 

 narrow marginal flange. Posterior sinuses distinct, inner corner of 

 lateral regions of cephalothorax overlapping outer corners of thoracic 

 area and closing off openings to sinuses. Posterior sinuses with light, 

 membranous flange attached to outer lateral margin and covering half 

 of sinus. Posterior margin of thoracic area slightly convex, middle of 

 margin projecting slightly. Cephalothoracic gi'ooves distinct; cross 

 groove slightly anterior to middle of cephalothorax, broadly cm*ved, 

 continuous with broadly curved posterior longitudinal grooves. An- 

 terior longitudinal grooves arising from cross groove, extending anteri- 

 orly and laterally in broad curve to lateral margins. Two slender, 

 heavily chitinized strengthening regions extending laterally from region 

 of junction of anterior and cross grooves, terminating in region of lateral 

 margin. Two grooves on anterior part of body extending from 

 anterior margin of cephalothorax posteriorly slightly past eyes. Other 

 short, indistinct grooves arising from lateral margin of cephalothorax 

 and extending medially for short distance. Eyes distinct, placed in 

 anterior fourth of cephalothorax, contiguous on median longitudinal 

 axis of body (fig. 6a). 



Fourth thoracic leg-bearing segment short, middle of segment drawn 

 out laterally at junction of fourth thoracic legs. Posterior three- 



