94 U.S. NATIONAL MUSEUM BULLETIN 23 6 



5. Antenna with slightly stronger exopodite, made up of 4 distinctly- 

 jointed segments. 



6. Legs 1 and 4 as in the female. Leg 2 (fig. 30/) with more strongly 

 developed exopodite and modified endopodite. Segments of exopodite 

 of leg 2 broader and external marginal spines stronger; 3 segments 

 about same length. 1st endopodal segment reaches middle of 2nd 

 exopodal segment; external apex of 2nd endopodal segment drawn 

 out to long, pointed process, twice as long as segment itself and 

 reaching far beyond apex of exopodite. 1st and 2nd endopodal seg- 

 ments each with internal seta; 3rd endopodal segment small, with 4 

 setae. 



Leg 3 (fig. 30^) with strongly developed exopodite; endopodite, 

 reaching half 3rd exopodal segment, as in female. Segments of 

 exopodite, compared with condition found in female, longer and 

 broader, of nearly same length. External marginal spines strongly 

 developed; 1st and 2nd exopodal segments each with 1 spine, 3rd 

 exopodal segment with 3 spines, gradually increasing in size; 3rd 

 spine particularly big, apical, IJ^ times as long as 3rd segment. Usual 

 apical spine on 3rd exopodal segment thin and slender, with ac- 

 companying seta pressed aside by 3rd outer edge spine. In addition, 

 there are 3 setae at the internal margin of the 3rd segment. 



Leg 5 (fig. 30A) with small external lobe of baso-endopodite; no 

 internal setae occur. Exopodite squarish, twice as long as broad. 

 There are 3 spiniform setae and 2 or 3 fine internal setae, gradually 

 merging into dispersed, hairlike spinules of internal margin. External 

 margin with small spinule above superior seta. 



Remarks. — The present new species undoubtedly is allied closely 

 to Harpacticus trisetosus Lang, 1948, which was based on a single 

 female specimen from the Siboga Expedition (Paternoster Islands) 

 which in turn, was described by A. Scott (1909, p. 202, pi. 61, figs. 

 15-21) as H. glaber. The following points of difference between the 

 females of both species have been noted: 



1. H. trisetosus measured 0.56 mm.; the present specimens are 

 0.37-0.39 mm. 



2. In H. trisetosus the 1st exopodal segment of the antenna has a 

 single seta; there are two in H. confusus, but in A. Scott's figure a 

 basally inserting seta on the 2nd exopodal segment of the antenna 

 may in reality belong to the 1st exopodal segment. 



3. There are slight differences in the shape of the maxillipede, e.g., 

 the absence of setae on the endopodite in H. confusus; such setae are 

 clearly figured by A. Scott. The general shape of the basis seems to 

 agree although the notch is more squarely cut in H. confusus. 



4. No details of legs 1 to 4 can be lifted from A. Scott's description 

 and figures, but the shape of leg 5 seems to agree quite well. I 



