Boone, Crustacea, Cruise of "Alva," 1931 125 



slender; the ischium being slender with a pointed tooth at the 

 upper outer distal margin; the ischium is 0.53 mm. long; the 

 merus is very little longer, 1.1 mm. long; the carpus: first joint, 

 1.6 mm. long ; second joint, 0.95 mm. ; third joint, 0.25 mm. ; fourth 

 joint also 0.25 mm. ; fifth joint, 0.5 mm. long. The propodus is 0.9 

 mm. long, the palm being 0,5 mm. and the finger 0.4 mm. long, 

 very tapered, with clusters of fan-wise bristles at the tip. 



The third pair of legs is slender, when extended, reaching 

 about as far as the proximal portion of the fingers of the first 

 pair of chelipeds ; the basis is short ; the ischium is 1 mm. long ; 

 the merus is flattened, 2 mm. long, 0.7 mm. wide ; the carpus is 

 1 mm. long, rounded, wider distally and with one strong spine on 

 the upper distal margin; the propodus is 2 mm. long, laterally 

 compressed, narrowed slightly proximally and distally, with 

 about nine, small, sharp, articulated spines set subequally along 

 the inferior lateral margin ; the dactyl is 0.6 mm. long, very curved, 

 with an acuminate, unguiculate tip ; about midway the inferior 

 lateral margin there is one small, articulated spine so placed that 

 it could easily be mistaken for the second point of a bifid dactyl. 

 The fourth and fifth pairs of legs are similar to the third pair, 

 but each pair is respectively shorter by about the length of its 

 dactyl than the preceding pair. 



Remarks: The present species, Athanas gracilis Boone, is 

 superficially very similar to the tropic Atlantic species, A. nite- 

 scens Leach and its variety, veloculis Bate, which is known from 

 the Christiana Fjiord (Lat. 60°) to the Cape Verde Islands, in- 

 habiting the coasts of England, France, the Hispanic peninsula 

 and the Mediterranean and Adriatic Seas. Pearson (1905) re- 

 cords nitescens from Cheval Paar, Gulf of Manaar, but I am in- 

 clined to think that his specimen may be identical with the one here 

 described. 



Athanas gracilis Boone belongs to the "nitescens group" of 

 Coutiere and de Man but differs from A. nitescens in : 



(a) The rostrum has a different length ratio to the orbit; the 

 supracorneal spine is wanting, and the infracorneal spine in 

 gracilis is different from that cited by Heller and Bate, respective- 

 ly, since in gracilis it reaches only midway the cornea and there is 

 no antennal tooth present here, such as figured by Bate. 



(b) The antennular peduncle, antennal peduncle and scapho- 

 cerite are all three subequal in length in gracilis. 



