COPEPODS OF THE WOODS HOLE REGION 297 



ment with a wide dorsal flap projecting posteriorly and fringed with 

 hairs, the second segment with a short posterior process, the fourth 

 segment globularly inflated, the terminal segments transformed into 

 a curved claw. Second and third legs stouter than in the female, 

 the middle segment of the second endopod with a terminal acuminate 

 spine; the third exopod with coarse outer and apical spines and re- 

 duced inner setae. Fifth legs partly fused across the midline, each 

 with six or seven setae, the first and third outer ones filiform, the 

 other plumose ; sixth legs present, each with two stout inner plumose 

 setae and a smaller outer filiform seta. Total length, 0.4^0.55 mm. 



Remarks. — This species is often found in considerable abundance. 

 Fish put it among the winter forms and said of it : " This was appar- 

 ently the only harpactid that had a pelagic period during the year. 

 Others may have been free-swimming, but did not occur in sufficient 

 numbers to indicate it." Gurney has recorded this copepod as found 

 in pools 6 miles or more from the ocean and filled with pure rain 

 water. 



RATHBUNULA, new genus 



Body moderately elongate and somewhat depressed ; metasome not 

 much wider than urosome, but twice as long; epimeral portions well 

 developed, covering the bases of the mouth parts and swimming legs. 

 Head fused with the first segment ; genital segment distinctly divided ; 

 caudal rami short and widely separated, apical setae half the body 

 length or more. First antennae 6-segmented, profusely armed with 

 pectinated spines and plumose setae, those of the male strongly hinged 

 and subcheliform. Exopod of second antennae 3-segmented, long 

 and stout, the middle segment short ; mandibular palp biramose and 

 well developed; maxilliped stout and uncinate, the terminal claw 

 with accessory bristles. Rami of first four pairs of legs 3-segmented, 

 all the spines pectinated; fifth legs 2-segmented, well armed with 

 setae ; rudiments of sixth legs present in the male. One large ovisac. 



Genotype. — Rathbunula agilis, new species. 



KEY TO THE SPECIES (BOTH SEXES) 



1. Body slender, five times as long as wide; fiftli segment half as 

 long as wide ; metasome segments separated by deep constric- 

 tions agilis, new species (p. 297) 



Body stout; only three times as long as wide ; fifth segment four 

 times as wide as long ; metasome segments telescoped to- 

 gether curticauda, new species (p. 300) 



RATHBUNULA AGILIS, new species 



Plate 19 



Occurrence. — About 200 specimens, including both sexes and de- 

 velopmental stages, were washed from the sand of Buzzards Bay 



