142 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii5 



this appendage, in opposition to the uniramous fourth thoracic legs, 

 is a true biramous appendage. 



Caligus kala, new species 



Figures 2a-k, 3a-/ 



Material. — Adult male (holotype, USNM 105106) collected by- 

 author from side of specimen of Naso hexacanthus (Bleeker), taken 

 in fish trap between Diamond Head and Koko Head, Oahu, Hawaii, 

 by Samuel Kaolulo. 



Measurements. — Length from anterior margin to posterior end 

 of caudal rami, excluding setae, 2.85 mm. Greatest length of cepha- 

 lo thorax, including frontal region, 1.89 mm. ; greatest width, excluding 

 marginal flange, 1.60 mm. Greatest length of genital segment, 

 excluding setae of fifth legs but including lobate projections, 0.49 

 mm.; greatest width, 0.62 mm. Greatest length of abdomen 0.29 

 mm. ; greatest width 0.35 mm. 



Description. — General background color of alcohol-preserved 

 specimen dark red. Reddish spots present on dorsal surface of 

 cephalothorax and lunules; concentration of spots from posterior 

 edge of frontal plates to eyes, around eyes to narrow median band; 

 median band split into two bands, one on either side of cephalothorax, 

 continuous along margin of cephalothorax to posterior lateral exten- 

 sions. Other reddish spots scattered irregularly over dorsal surface, 

 concentrated at sutures. Eyes red. Genital segment with reddish 

 tinge; abdomen with reddish tinge, darker along alimentary tract. 

 Caudal rami colorless. 



Cephalothorax elliptical, frontal plates large, division between 

 frontal plates and cephalothorax distinct (fig. 2a). Lunules large, 

 covering most of frontal plate area; free surface extending posteriorly 

 on ventral surface past junction of frontal region and cephalothorax 

 (fig. 2c). Division between frontal region and cephalothorax con- 

 tinuous, irregular in region of lunules, curving anteriorly in middle. 

 Lateral margins of cephalothorax with narrow marginal flange. 

 Posterior sinuses distinct, U-shaped though apex sharp, not broadly 

 curved. Posterior sinuses with small, membranous flange attached 

 to outer lateral surface and projecting dorsally and medially (fig. 2a). 

 Posterior margin of median area of cephalothorax slightly convex, 

 projecting slightly past posterior extension of lateral regions; lateral 

 corners of median area sharp, margin not continuous with inner 

 margin of posterior sinuses. Major cephalothoracic grooves distinct, 

 in irregular H -shape. Cross and posterior longitudinal grooves 

 continuous, broadly curved. Cross groove present in middle of 

 cephalothorax, middle of groove extending anteriorly from junction 

 of longitudinal grooves, apex flatly pointed. Anterior longitudinal 



