4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 122 



Rostral area (fig. 21) as in female. First antenna like that of female 

 but with four aesthetes, one being added on midanterior margin of mid- 

 dle segment. Second antenna, labrum (see fig. 21), mandible, first 

 maxilla, and second maxilla resembling those in female. Paragnath 

 absent. Maxilliped (fig. 22) 4-segmented. First segment short and 

 unarmed. Second large and swollen with two inner setae (one sclero- 

 tized proximally, other entirely hyaline) and having its distal outer 

 surface minutely punctate. Third segment very short and unarmed. 

 Fourth segment forming a terminal claw 39// along its axis, bifurcated 

 at its tip, with an outer hyaline lamella and an inner triangular hyaline 

 process; bearing two setae (one sclerotized proximally, other entirely 

 hyaline) . 



Legs 1-4 as in female, with same spine and setal forumla. Leg 5 

 (fig. 23) without a distinct segment and consisting of three small setae, 

 the two more ventral ones forming a pair and probably homologous to 

 the two setae on the end of leg 5 in the female. Leg 6 (figs. 19, 23) 

 represented by a ventrolateral flap bearing two small setae. 



Spermatophore (fig. 24) elongated, 255/x x Q2fx, not including neck. 



Color as in female. 



Etymology. — 'The specific name diminuta, from Latin = diminished, 

 refers to the relatively small size of this species. 



Method of collection and relation to host. — The number of 

 specimens of X. diminuta collected from Psammocora contigua depended 

 upon the technique employed. When the corals were washed in 

 weakly alcoholized sea water (with about 5 per cent ethyl alcohol) 

 within one or two hours after being brought to the laboratory, few if 

 any Xarifia were obtained. After crushing the corals with, a hammer, 

 relatively few Xarifia were recovered from the debris and mucus. 

 When, however, the corals were left overnight (12-14 hours) in pails of 

 alcoholized sea water, abundant specimens of the copepods were found 

 in the sediment. This is in accord ^dth the observations of Humes 

 (1962a) on the collection of other species of Xarifia. Gerlach, as 

 quoted by Humes (19G0), observed that living Xarifia in Pocillopora 

 in the Maldive Islands crawl about on the surface of the coral but 

 may at times enter the polyps where they seem to tear up the tissue 

 of the coral. 



Comparison with related species. — There are 10 species pres- 

 ently known m the genus Xarifia. X. diminuta may be distinguished 

 from eight of these which have the endopods of legs 1-4 composed of 

 a single segment (X maldivensis Humes, 1960; X. fimhriata Humes, 

 1960; X. gerlachi Humes, 1962; X. longipes Humes, 1962; X. reducta 

 Humes, 1962; X. serrata Humes, 1962; X. tenuis Humes, 1962; and X. 

 injrequens Humes, 1962). In the two remaming species, X. dispar 

 Humes, 1962, and X. comata Humes, 1962, the endopods of legs 1-4 are 



