192 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



Ventral spine on terminal segment of maxilliped rather reduced; 

 large process stout and, as in the other species, strongly ciliated. 



Swimming legs like those of adhaerens; armature represented by 

 same formula (p. 178) and ornamentation similar except that spinules 

 on coxal plates of second and third legs form patches rather than 

 being confined to edge, setules on exopod spines shorter and strong 

 ciliation at base of median seta on third endopod segment apparently 

 absent on all legs. 



Fifth and sixth legs also veiy similar to those of adhaerens but 

 former lacking spinules on basal segment and on edges of distal 

 podomere. 



Description of the male: Body longer (2.83 mm., mean of 10 

 specimens, range 2.67-3.24 mm.) than that of female; width of 

 prosomc 0.9 mm. (0.84-0.94 mm.). Genital segment almost square 

 in dorsal view. No spermatophores found. Caudal rami like those 

 of female. 



Antennule similar to, but patches of spinules on second and third 

 segments of antenna more extensive than in female. 



Mandible occasionally with a small setule in addition to the normal 

 seta. Maxillule and maxilla as in female. 



Maxilliped similar to that of male subadhaerens but with 1 long seta 

 on last segment and lacking "cock's comb" on second. 



Swimming legs larger than those of female ; spines longer and better 

 developed, but armature the same. Endopodites of second and third 

 legs, like condition in male subadhaerens, longer than those of female 

 but here last seta on third podomere of second leg reduced to a minute 

 setule. 



Fifth leg with basal podomere partly fused to thoracic segment. 

 Ornamentation reduced to a ventral line of spinules at base of terminal 

 spine. 



Sixth legs like those of subadhaerens male but completely hidden in 

 dorsal view; patches of fine denticles on their ventral surface. 



Figure 10.- — Hemicyclops arcnicolae, new species, male: a, Habitus, dorsal aspect, b, Right 

 antennule, dorsal (anterior) view, c, R.ight antenna, dorsal (posterior) view, d, Labrum, 

 ventral view, e, Labium, ventral view. /, Left mandible, ventral (posterior) view, g, 

 Left paragnath, ventral (posterior) view, h, Right maxillule, ventral (anterior) view. 

 i, Right maxilla, anterodorsal view. /, Right maxilliped, ventrolateral view, k, Left 

 maxilliped from inner side. /, Right first swimming leg with coxa! plate, ventral (ante- 

 rior) view. «;, Left second swimming leg with coxal plate, ventral (anterior) view, n, 

 Right third swimming leg with coxal plate, ventral (anterior) view. 0, Right fourth 

 swimming leg with coxal plate, ventral (anterior) view, p, Right fifth leg, ventral view. 

 q, Left sixth leg, ventral view, r, Right caudal ramus, dorsal view. Scale A (fig. 2) 

 applies to a; C to b, d-e, j-o, and r; D to c; and E lof-i and p-q. 



