COPEPODS OF THE WOODS HOLE BEGION 229 



STENHELIA ARENICOLA, new specieg 



Plate 6 



Occurrence. — Four females were washed from the sand on Buz- 

 zards Bay bathing beach July, 1927 (female holotype, U.S.N.M. 

 No. 63426) ; 2 females from the sand of Nobska bathing beach, east 

 of the lighthouse, July, 1927. 



Color. — Body transparent and without pigment markings. 



Female. — Body short and stout, three times as long as wide; 

 cephalic segment longer and wider than the rest of the metasome; 

 free segments very short and diminishing regularly in width, the 

 fifth segment but little narrower than the fourth. Urosome three- 

 fifths as long as metasome, not tapered posteriorly but slightly 

 widened; genital segment not divided, as wide as the fifth segment 

 anteriorly but narrowed posteriorly. Basal abdominal segment 

 longer than either of the other two and narrower; caudal rami 

 widely separated and slightly divergent, twice as long as wide, the 

 inner apical seta longer than the urosome, the outer one half as long. 

 Kostrum well defined at its base, narrowed through the middle and 

 notched at its tip. First antennae 8-segmented, the segments well 

 defined and densely setiferous, the terminal segment longer than the 

 two preceding it combined. Distal segment of exopod of second 

 antenna slightly longer than the proximal segment and four times 

 as long as the middle segment. Chewing blade of the mandible 

 short and very irregularly toothed; basal part of palp narrowed in 

 the center, the inner ramus no longer than the outer and abruptly 

 reflexed,^ with one of the terminal setae elongate and flagelliform; 

 maxillae and maxillipeds as in other species of the genus. 



Endopod of first leg scarcely reaching the end of the second exo- 

 pod segment, its terminal segment as wide as long, the middle apical 

 seta stout and greatly elongated; the proximal segment is hairy on 

 its anterior surface. The three segments of the first exopod are 

 about equal in length, the middle one with a short inner seta, the 

 distal one with two slender outer spines and two unequal apical 

 setae. The rami of the second and third legs are about equal in 

 length, the endopod of the fourth legs is much shorter than the 

 exopod. In the fifth legs the distal segment is as wide as long and 

 narrowed at its base, with six setae, the second and third inner ones 

 filiform, the third one very short. The basal expansion is rapidly 

 attenuated inwardly and does not reach the midline; it is armed 

 with four slender setae, the two middle ones longer than the others. 

 Total length, 0.55-0.65 mm. 



Remarks. — The species can be recognized by the increase in width 

 of the posterior part of the urosome, by the wide separation of the 



' The inner ramus shown in Plate 6, c, was straightened under pressure. 



