SHRIMPS FROM THE MARSHALL ISLANDS — CHACE 17 



These specimens agree very well mth Coutiere's description and 

 figures except that the rostrum reaches at most as far as the end of 

 the second antennular segment and frequently is slightly shorter. 

 The males have carapace lengths of from 1.4 to 2.3 mm. and the ovi- 

 gerous females from 1.5 to 2.2 mm. In the smallest male, from Enirik 

 Island, Bikini Atoll, the left first cheliped is very small and similar to 

 the minor cheliped of the female; the right cheliped in this specimen 

 is lacking. It is not possible to tell from the material at hand whether 

 this anomaly is due to the immaturity of the specimen or whether it 

 is indicative of polymorphism in the males of this species as suggested 

 by Tattersall. Only two of the remaining five males in the collection 

 retain the major cheliped, and in both of these it is as figured by 

 Coutiere. Three of these males have the minor cheliped; it agrees 

 with Coutiere's figure, except that the merus is noticeably broader. 

 In the three females in which the major cheliped is intact, it corre- 

 sponds with Coutiere's figure except that the fingers are crossed at 

 the extreme tips. 



Athanas tnarshaUensis, new species 



Figure 8 



Eniwetok Atoll: Bogombogo Island; intertidal; May 31, 1946; M. 

 W. Johnson; 1 male holotype, 9 male and 9 ovigerous female parat3^pes. 



Bikini Atoll: Namu Island; outside reef; Apr. 4, 1946; M. W. 

 Johnson; 1 male paratype. 



Rongelap Atoll: Tufa Island; lagoon side, under rocks; July 16, 

 1946; M. W. Johnson; 2 ovigerous female paratypes. 



Carapace and abdomen sparsely pubescent. Rostrum (fig. 8,a,b) 

 reaching slightly beyond middle of second antennular segment, with 

 a dorsal carina on the anterior two-thirds of its length. No supra- 

 corneal spines. Extracorneal tooth prominent and sharp, but falling 

 well short of anterior margin of cornea. Infracorneal tooth small 

 and blunt, not reaching nearly as far as extracorneal. Anterolateral 

 margin of carapace rounded, unarmed. Sixth abdominal somite 

 slightl}^ longer than fifth (fig. 8,c) ; posterior angle of pleuron of fifth 

 somite acute. Telson (fig, 8,c~d) nearly 1)^ times as long as sixth 

 somite and 2.7 times as long as its distal margin; it is armed with the 

 usual two pairs of dorsal and two pairs of distal spines, with numerous 

 marginal setae between the two sets of distal spines. 



Antennular peduncle (fig. 8,e) wdth distal segment about one-third 

 again as long as penultimate; stylocerite extending slightly beyond 

 penultimate segment; outer antennular flagellum divided at third 

 joint, the inner branch probably composed of tlu-ee segments, each of 

 which appears to be subdivided so that this branch has the appearance 



