182 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



Antennule, antenna, mandible, maxillule, and maxilla essentially 

 the same as in female, although maxilla has a peculiar hump on 

 outer side of base of second segment which is not found in that of 

 female. 



Maxilliped, as is usual in poccilostomes, a prehensile structure, sim- 

 ilar to that of thysanotus, but: first segment with a small hooklike 

 process and 2 setae on inner face; second segment not as wide 

 and bearing a peculiar "cock's comb" projection also on inner 

 face; last segment with attenuated tip, ornamented with scalelike 

 thickenings, and 2 setae (if element on inner side of angle — like that 

 similarly placed in thysanotus — actually represents a seta). 



Endopodites of second and, to a lesser extent, third legs very much 

 more elongate than those of female, as are spines — particularly the 

 innermost— on these rami; but setae on third segment somewhat 

 reduced. Armature of all legs as represented in table for female 

 adhaerens (p. 178) and ornamentation shown in figure bj-i; both like 

 those of female. 



Spines on outer edge distal segment of fifth legs rather more offset; 

 lengths of terminal spine and seta next to it not as divergent as, 

 and ornamentation rather less than, in female. 



Sixth legs covering a much smaller area of genital segment than in 

 thysanotus and spine usually extending posteriorly, but general 

 structure of appendage similar to male of that species. 



Remarks: As the descriptions and figures show, this species is very 

 close to adhaerens (hence its name). The differences between the 

 females (it is unfortunate that the male adhaerens is unknown) seem 

 almost of subspecific rank. However, with no intermediate morpho- 

 logical forms, well-separated ranges and the apparent difference in 

 habitat, I think that their relation can at present be best indicated 

 by making subadhaerens of equal rank. 



Since this species apparently occupies the same range as tltysanotus 

 and is also associated with Callianassa (see below), it might represent 

 one of the forms now equated with thysanotus (callianassae or puget- 

 tensis). However, reference to the literature showed that the only 

 evidence in favor of this view was Wilson's figure (1935, pi. 27, 



Figure 5. — Hemicyclops subadhaerens, new species, female: a, Left mandible, ventral (pos- 

 terior) view, b. Left maxillule, dorsal (posterior) view, c, Left maxilla, dorsal (anterior) 

 view, d, Right maxilliped, ventral (posterior) view (flattened), e, Detail of ventral 

 terminal spine on the maxilliped. /, Left first swimming leg with coxal plate, ventral 

 (anterior) view, g, Left second swimming leg with coxal plate, ventral (anterior) view. 

 h, Left third swimming leg with coxal plate, ventral (anterior) view, i, Left fourth 

 swimming leg with coxal plate, ventral (anterior) view. /, Left fifth leg, ventral view. 

 k, Left sixth leg, ventrolateral view. /, Left caudal ramus, dorsal view. Scale D (fig. 2) 

 applies lof-j and /; E to c-d; F to a-b and k\ and G to e. 



