COPEPODS OF THE WOODS HOLE REGION 345 



antennae the longest, fourth segment the shortest; end segment of 

 second antenna with four apical setae. The spine on the inner 

 margin of the first endopod's basal segment is short and blunt, and 

 turned distally inside the other two segments; the spine on the 

 second segment is foot-shaped, and that on the third segment is 

 claw-shaped. The fifth leg is three times as long as wide, with 

 four spines, one of which is apical. Total length, 1.25-1.5 mm. 



Male. — Cephalic segment scarcely wider than long, the remaining 

 segments free and diminishing regularly in width, the second and 

 third with epimeral plates pointed backward. Genital segment 

 quadrangular, completely divided across the center, with a fingerlike 

 process tipped with a single spine on each lateral margin of the 

 anterior part, and a spine at each corner of the posterior part; the 

 last two abdominal segments are almost completely divided longi- 

 tudinally at the center; each caudal ramus carries three apical setae 

 and one on the outer margin. Total length, 0.6-0.7 mm. 



Remarks. — Only a few crabs have been examined for these cope- 

 pods, and it is probable that further search will show the parasite 

 to be fairly abundant. 



Genus HEMICYCLOPS Boeck, 1873 



Body cyclopoid, metasome dilated and more or less flattened ; head 

 fused with first segment, much wider than long; second, third, and 

 fourth segments but little narrowed, fifth segment abruptly reduced 

 to half the width of the fourth. Urosome slender, 4- or 5-segmented 

 (genital segment divided) ; caudal rami short and stout. First an- 

 tennae 7-segmented ; second antennae 4-segmented, with long curved 

 apical setae; maxillipeds 3-segmented and scarcely prehensile in 

 female, powerfully developed and prehensile in male. Rami of first 

 four pairs of legs 3-segmented; fifth legs 2-segmented, uniramose; 

 distal segment a broad lamella with marginal setae, the terminal 

 one filiform, the others plumose. A single species. 



HEMICYCLOPS ADHERENS (Williams) 



Figure 206 



Lichomolffus adherens Williams, 37th Ann. Rep. Comm. Inland Fisheries Rhode 

 Island, p. 75, pi. 2, 9 figs, 1907. 



Occurrence. — Found abundantly under small stones between tides 

 at the mouth of Narragansett Bay, R. I., by Williams. 



Distribution. — Not found as yet in any other locality. 



Color. — Not recorded. 



Female. — Metasome elliptical, three-fourths as wide as long, with- 

 out epimeral plates; urosome half as long as metasome, 5-segmented, 

 the genital segment being divided at the center ; anterior portion of 

 genital segment a little dilated; anal segment with a posterior fringe 

 of spines ; caudal rami twice as long as wide and slightly divergent. 



