ox CRUSTACEA BROUGHT 15V DU WII.LEV KlioM THK .SOTTTH SEAS. 613 



NaNNASTACUS 0E01!(il li. sp. 

 Plate LXIV li. 



Carapace less tumid than in the ])receding species but with similar depression 

 and elevations. Pseudo-rostral projection in like manner reminded, but less ob]iijuel\ 

 produced and not ridged on the surface. Antero-lateral corners acute, minutely pro- 

 duced. Lower and hind margins forming an nbtuse angle, little rounded. Surface as 

 in preceding species. Fifth peraeon segment and first of pleon with a marked longi- 

 tudinal medio-dorsal depression. Segments of pleon with pellucid latei-al carinae formed 

 as in the preceding species, fifth segment considerably the longest. 



Eyes larger than in the other species ; antennae similar, but the flagellum of the 

 second pair much longer, composed of eighteen joints or possibly more, the terminal 

 joints so excessively slender that their boundaries are diHicult to distinguish. The 

 mouth-organs agree with tho.se in the companion species. The branchial leaves appear 

 to bo about .sixteen in number. 



The peraeopods are less slender. Especially it will be noticed that in the fifth 

 pair the antepenultimate joint is little longer than the penultimate, instead of much 

 longer as in iV. ossiuni. 



The uropods differ greatly, for heie tlie peduncle i.s produced beyond the terminal 

 segment of the pleon at least as much as in iV. unguicidatus, and the outer ramus, 

 instead of being siibequal in length to the peduncle, as in N. ossiuni, is not half as 

 long, in eacli case otnitting the terminal spine, which is here of great length. The 

 inner ramus is very long, slender, spinose. 



Length, 2'o mm. 



Habitat, the same as that of Nannastacus ossiani. 



The specific names are chosen in compliment to Professor Georg Ossian Sars. 

 Excejit for some differences in the shape of the carapace, N. georgi seems to agree 

 closely with the male form described by Sars from the Phili])])ines, and if they should 

 prove to be simply varieties of a single species the name now given will supph' what 

 is re(iuired for the form described and figured 1)\ Sars. 



IS()1'()1).\. 



F.\M. Tanaii).\k. 



18o3. Taiuiidae (part), Dana, U. S. Expl. E\\>., \ol. 13, pt. 2, p. 71)2. 



1857. Asellidae (part), White, Popular Hist. Brit. Crustacea, p. 225. 



IStifi. Tananhie (part), Bate and Westwood, Brit. Sess. Crust., vol. 2, p. 117. 



1.S.S0. Titnaidiie, Harger, Rep. U. S. Fisheries for 1878, pt. (J, pp. :i04, 41o. 



1880. Tanaidue, Sai-s, Lsopoda chelifera. Arch. Naturv., vol. 7, sep. copy p. 20. 



188C. Tanaidue, BeddMrd, Challenger Reports, vol. 17, Lsopoda. )i. 11!'. 



81—: 



