HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 213 



men with light reddish area around posterior medial margin of con- 

 spicilla in alcohol. 



Cyst of general ovoid shape, appearing to be formed of epidermis of 

 host; found only on fins of host, usually parallel to fin rays. Small 

 opening present on end of cyst, caudal rami setae visible protruding 

 through opening. Color of cyst similar to that of host (fig. 19a). 



Since the complete life history of this copepod has not been worked 

 out, the stages passed within the cyst have been divided arbitrarily 

 into two groups: the early encysted stage; and the late encysted 

 and recently excysted stage. Cephalothorax of early encysted forms 

 orbicular, frontal region distinct in older specimen, indistinct in 

 younger. Frontal region in older specimen with deep median groove ; 

 younger specimen without groove, middle of anterior margin convex. 

 Anterior surface of frontal region with indistinct transverse ridges in 

 older specimen, not visible in younger. Division between frontal 

 region and cephalothorax incomplete in both specimens. Older speci- 

 men with distinctly raised, anteriorly bilobed surface at region of 

 junction of frontal region and cephalothorax. Lateral margins 

 of cephalothorax without marginal flange ; posterior sinuses of younger 

 specimen slight, apically pointed indentations, shallow but distinct 

 V-shaped sinuses present in older specimens. Posterior margin of 

 cephalothorax, medial to posterior sinuses, trilobed; lateral areas 

 extending further posteriorly than trilobed median portion. Longi- 

 tudinal grooves of cephalothorax present in younger specimens 

 as indistinct grooves extending from apex of posterior sinuses an- 

 teriorly, terminating blindly in posterior fourth of cephalothorax. 

 Grooves of older specimen extending from apex of posterior sinuses 

 anteriorly to just behind eyes, then turning laterally, terminating 

 blindly medial to lateral margins. Older specimen with indistinct 

 medial, longitudinal groove extending from region behind eyes 

 to posterior surface of genital segment. Eyes in both younger and 

 older early encysted forms distinct, consisting of pair of large, cir- 

 cular eyes with inner margins separated, one on either side of median 

 longitudinal axis of body, and small, median, thu'd eye between, and 

 immediately posterior to, paked eyes. Conspicilla indistinct in both 

 specimens, appearing as slightly roughened region anterior and lateral 

 to eyes (figs. 19b,c). 



Second, third, and fourth thoracic leg-bearing segments of early 

 encysted forms free, successively decreasing in size. Second thoracic 

 leg-bearing segment of younger specimen three times as wide as long; 

 width of segment in older specimens slightly more than twice length. 

 Lateral margins of second thoracic leg-bearing segment of younger 

 specimen broadly rounded, of older specunen concave in anterior 

 region, flaring in convex curve posteriorly. Posterior margin of second 



