234 BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



ATTHEYELLA BICOLOR, new species 

 Plate 7 



Occurrence. — Found in abundance in two of the brackish ponds 

 on Chappaquiddick Island, July, 1925. Type of the new species, 

 U.S.N.M. No. 59763. 



Color. — Body transparent, cephalic segment white, the rest of the 

 body pale blue; ovary and oviducts light brown; contents of the 

 midgut orange-red ; eye bright ruby red. 



Female. — General form short and stout, tapering regularly back- 

 ward without any demarcation between metasome and urosome; 

 cephalic segment broadly rounded anteriorly and wider than any 

 of the other segments ; rostrum prominent, poorly defined at its base 

 and obtuse at its tip. Second (first free) metasome segment longer 

 than any of the others ; urosome three-fifths as long as metasome, its 

 segments fringed laterally and ventrally with small spinules; geni- 

 tal segment distinctly divided, abdominal segments diminishing in 

 length and width backward ; caudal rami one-half longer than wide, 

 their inner margins slightly convex and armed with many spines and 

 setae; both apical setae jointed near their base, the inner one longer 

 than the urosome. The anal operculum and the corners of the anal 

 segment are densely fringed with coarse spinules. 



First antennae 8-segmented and rather stout, especially the two 

 basal segments; they are only half the length of the cephalic seg- 

 ment and sparsely setose; the second segment carries four setae on 

 its dorsal surface and three on the anterior margin; the aesthetask 

 on the fourth segment reaches beyond the tip of the antenna. The 

 second antennae have a 1-segmented exopod attached to the side 

 of the basal endopod segment, and armed with three setae. The two 

 segments of the maxilliped are the same length, the distal one 

 convex on its inner margin and fringed with long hairs, the ter- 

 minal claw as long as the second segment and slightly curved. 



Rami of first legs equal, exopod 3-segmented, endopod 2-segmented, 

 proximal segment of latter twice as wide and half as long as distal 

 segment ; this endopod is tipped with two setae, the inner one longer 

 than the outer. In the second and third legs the endopods are a little 

 longer than the basal exopod segments, in the fourth legs they 

 scarcely reach the center of that segment. In the second and third 

 legs the distal endopod segment is four times as long as the basal, 

 with three apical setae, the middle one much the longest. In the 

 fourth legs the distal segment is less than three times as long as the 

 basal, with two apical setae, the outer one five times as long as the 

 inner. In the fifth legs the distal segment is as wide as long, with 

 five setae, two apical and three outer, an apical seta the longest. The 

 basal expansion extends half its length beyond the tip of the distal 



