COPEPODS OF THE WOODS HOLE REGION 257 



fifth segments narrowed. Urosome, including the caudal rami, 

 about as long as the metasome ; genital segment with nearly straight 

 lateral margins. First abdominal segment nearly as long as the 

 other two combined ; anal segment deeply incised posteriorly ; caudal 

 rami lamellar, three times as long as wide, the inner apical seta twice 

 the length of the outer, each ramus with a coarse pectinate spine at 

 the outer distal corner and a small spine at the center of the outer 

 margin. 



Kostrum short, blunt, and not defined at its base. First antennae 

 8-segmented, the second segment the longest with a small rounded 

 protuberance on its posterior margin; third segment with a small 

 spine and seta on its posterior margin; fourth segment with a 

 slender aesthetask reaching well beyond the tip of the antenna. 

 Endopod of second antenna 3-segmented, the 1-segmented exopod 

 attached to the tip of the basal segment, and armed with two apical 

 and one lateral setae. Maxilliped with a short and stout apical 

 claw and a long slender accessory spine. 



Exopod of first legs a single segment, but the arrangement of the 

 spines on the outer margin, compared with those on the other 

 legs, indicates that it is really three segments fused; the inner 

 margin is perfectly smooth and unarmed. The endopod is 2-seg- 

 mented, longer than the exopod, its distal segment longer than the 

 basal, with two small apical claws and two spines on the inner 

 margin near the tip. Exopods of second, third, and fourth legs 

 distinctly 3-segmented, with an outer spine on each segment and 

 two unequal apical spines; endopods 1-segmented and club-shaped, 

 each tipped with a single seta. Basipods of all four pairs of legs 

 somewhat geniculate, but not carrying the rami to the lateral mar- 

 gins of the body. Outer seta of the second basipod near the tip of 

 the segment in the first legs, but at the center of the outer margin 

 in the three following pairs. Fifth legs 2-segmented, the basal seg- 

 ment with a very much reduced inner expansion, which reaches the 

 midline but is wholly unarmed. Distal segment very small, strongly 

 constricted at its base, with a minute spine and a medium plumose 

 seta at its apex, and a much smaller seta on the outer margin. Total 

 length, 0.25-0.35 mm. 



Male. — About the same length as the female but more slender, the 

 metasome segments separated by deep lateral sinuses. Urosome two- 

 thirds as long as metasome and considerably tapered posteriorly ; 

 abdominal segments subequal in length, the anal segment relatively 

 longer than in the female; caudal rami longer than the anal seg- 

 ment, with the outer spine close to their base. 



First antennae twice geniculate, the second and third segments 

 with broadly rounded projections on the posterior margin, the fifth 



