COPEPODS OF THE WOODS HOLE KEGION 299 



basipod segment and two rami, the outer one 2-segmented, the inner 

 one 1-segmented, the distal end of the basipod and both rami well 

 armed with setae. First maxilla with its epipodal lobe shaped some- 

 thing like a dumb-bell, each end with three setae; second maxillae 

 with three digitiform processes increasing in length outwardly. 

 Basal segment of maxillipeds with two fingerlike processes and a seta 

 at its inner corner, the second segment or hand with a fringe of long 

 and fine hairs along its inner margin, one longer seta at the center 

 and a shorter one near the distal end; the terminal claw is slender, 

 curved at its tip, and jointed near its center, with two fine bristles on 

 the inside at the joint. 



In the swimming legs the spines of all the exopods are pectinated 

 on their outer margins; the endopods of the first three pairs are 

 longer than the exopods, the segments fringed on their outer margins 

 with rather coarse spines ; the rami of the fourth legs are about equal. 

 The fifth legs are 2-segmented, the basal expansion broadly lamellar 

 and a little longer than the distal segment, with six short apical 

 setae, the inner one much smaller than the others, which are subequal. 

 The inner margins of the basal expansions of the two legs are set with 

 coarse spines which interlock on the midline; the outer process is 

 stout and armed with one seta and several spines. The distal seg- 

 ment is ovate, with a fringe of hairs on its outer margin and six 

 apical setae, the second and third inner ones terminal and borne on 

 short processes; these two and the outer one are filiform, the other 

 three plumose. Total length, 0.7-0.9 mm. 



Male. — A little shorter and more slender than the female. In the 

 first antennae the second and third segments are armed with doubly 

 pectinated spines, the fourth segment is globularly swollen on its pos- 

 terior margin, the fifth segment has a conical process at its posterior 

 distal corner, and the end segment is claw-shaped with an accessory 

 claw on its anterior margin. The second antennae, mouth parts, and 

 swimming legs are like those of the female without sex modifications. 

 The fifth legs are much reduced in size, especially the basal expansion, 

 which scarcely reaches the center of the distal segment and bears only 

 two setae; the distal segment is nearly as wide as long, somewhat 

 ovate, with an outer fringe of long hairs and five apical setae, the 

 middle one terminal, borne on a short process, and filiform. On the 

 ventral surface of the anterior half of the genital segment is a short 

 lamina on either side, armed with three setae, the outer one the long- 

 est; these laminae are the rudimentary sixth legs. Total length, 

 0.6-0.8 mm. 



Remarks. — This was by far the most abundant copepod in the 

 Buzzards Bay sand, and when once washed out into sea water it 

 swam about vigorously like any free swimmer. The most persistent 



