51 



5. Diastylis rostrata, (Goodsir). 



(IM. XXXIX.) 



Manna ntxlrata, (Joodsir, Edinburgh New 1'hil. .l.mrnal \x\'.\. Vol. XXXIV. 



Syn: Diasti/lis Icevis, Norman. 



Specific (Characters. Fi'inalf. Body moderately robust, with the anterior 

 division ovoid in form and but slightly arcuate above. Carapace comparatively 

 larger than in J). lucifcni and more evenly vaulted above, surface perfectly 

 smooth, but clothed with scattered hairs; pseudorostral projection rather pro- 

 duced, acuminate, horizontally extended, subrostral corners very slight. Exposed 

 part of trunk, like the carapace, smooth, with scattered hairs, last segment with 

 the anterior edge minutely serrate and setiferous, lateral parts slightly produced 

 behind. Tail about the length of the anterior division, exclusive of the pseudo- 

 rostral projection, and perfectly smooth. Eye well developed and somewhat 

 convex. Superior antennae very slender, with the peduncle extending far beyond 

 the tip of the pseudorostral projection, its 1st joint much shorter than the other 

 2 combined and unarmed, last joint very narrow, linear. First pair of legs much 

 longer than the carapace, basal joint densely fringed with plumose seta3, pen- 

 ultimate joint considerably longer than the antepenultimate one, last joint some- 

 what exceeding half the length of the penultimate one; 2nd pair rather densely 

 setiferous, antepenultimate joint about the length of the last 2 joints combined; 

 3rd and 4th pairs, like the 2 preceding pairs, without any denticles on the basal 

 joint. Uropoda with the outer ramus about half the length of the stem, inner 

 ramus somewhat shorter, and having the 1st joint as long as the other 2 com- 

 bined, spinules of the inner edge about 12 in number (7 on the 1st, 3 on the 

 2nd, and 2 on the last joint), apical spine strong, forming the immediate con- 

 tinuation of the joint. Telson rather produced, reaching as far as the stem of 

 the uropoda, proximal thickened part occupying about Vs t>f the length of the 

 telson, distal part very narrow, with about 12 spinules on each side, apical 

 spinules scarcely different from the lateral. Colour greyish white. Length 

 amounting to 1 mm. 



Adult male resembling in external appearance that of D. cornuta. the 

 carapace having on each side a distinct longitudinal carina crossed in front by 

 an obliquely transverse plica; but this carina is quite smooth, not, as in the 

 male of D. cornuta. serrate. Last pecligerous segment with the lateral parts 

 considerably produced behind. Caudal segments spinulous. Eye larger than in 

 the female, though, in the lateral view of the animal, partly concealed by a 



