300 BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



attempts, however, failed to secure any of them by towing in the 

 ordinary manner above the sand. They may be easily recognized by 

 the prominent rostrum and the profusely armed first antennae. 



RATHBUNULA CURTICAUDA, new species 



Plate 20 



Occurrence. — Fifty specimens, including both sexes, were washed 

 from the sand of Buzzards Bay bathing beach at Woods Hole, July, 

 1927. The male holotype is U.S.N.M. No. 63436. 



Color. — Body transparent and colorless, but with a bluish tinge, 

 and without the red streak on the dorsal midline, which is character- 

 istic of the preceding species; eye red; eggs pale bluish. 



Femjale. — Body fusiform and nearly as thick as wide, all the 

 segments telescoped together, without intervening constrictions. 

 Cephalic segment widest across the posterior margin, not narrowed 

 anteriorly so much as in agilis; rostrum tongue-shaped, projecting in 

 front of the first antennae, well defined at its base, and turned down- 

 ward at its tip. Second and third segments wider than the head, the 

 width about one-third of the body length; epimeral plates not well 

 developed, but showing a little at the posterior corners of the seg- 

 ments. Fifth segment shorter than the fourth, and four times as 

 wide as long; genital segment as long as the fourth and fifth seg- 

 ments together and only partly divided. Abdominal segments very 

 short and wide, the two basal ones about the same length, the anal 

 segment shorter, especially at the lateral margins. Caudal rami 

 twice as wide as long, and separated by a space twice their own width, 

 inner terminal seta two-thirds as long as the entire body. 



First antennae curved into a semicircle, apparently 6-segmented 

 but the jointing very indistinct, and even more profusely armed with 

 setae and pectinated spines than agilis. The two basal segments of 

 the exopod of the second antenna are the same length and each car- 

 ries an inner pectinated seta; the end segment is twice as long, with 

 two apical pectinated setae and a very long and slender inner seta, 

 inserted at the base of the segment and plumose only at its tip. The 

 mouth parts are like those of the preceding species except that the 

 chewing blade of the mandible is more coarsely toothed. In the 

 second legs the end segment of the exopod has no inner setae, and the 

 end segment of the endopod has but a single inner seta. 



The basal expansion of the fifth legs is fringed with hairs on both 

 lateral margins, and the inner edges do not interlace on the midline; 

 around the distal end are five mucronate setae of about the same size, 

 which bear plumes only on their abruptly narrowed tips. The distal 

 segment is small, reaching but little beyond the center of the basal 

 expansion, with five apical setae, the inner one mucronate, the second 



