57 



9. Diastylis echinata, Sp. Bate. 



(PL XLIII.) 

 Diastylis echinata, Sp. Bate, Ann. & Ma#. Nat. Hist. ser. 3, V(jl. XV, p. 81, PI. [, lijr. t. 



Specific Characters. Female. Body less robust than in the 2 preceding 

 species, and minutely spiny all over, anterior division evenly vaulted above, and 

 having its greatest width in front of the middle. Carapace very large and tumid, 

 the width considerably exceeding the height, surface finely spinulous, with scattered 

 somewhat larger spines, lateral faces partly mapped out by rows of small spin- 

 ules into polygonal areas having, as a rule, at each corner an anteriorly-pointing 

 spine, 3 or 4 somewhat larger spines forming on each side a lateral series 

 extending forwards to the base of the pseudorostral projection, the latter of 

 moderate size, comically produced, horizontal and finely spinulose laterally ; subro- 

 stral corners obsolete. Exposed segments of trunk each with 2 very conspicuous 

 juxtaposed spines dorsally forming together a double longitudinal row, epimeral 

 parts of the 3 posterior segments dentiformly produced. Caudal segments coarsely 

 denticulate both dorsally and laterally. Eye inconspicuous. Superior antennae 

 not much elongated, the peduncle scarcely extending beyond the tip of the pseudo- 

 rostral projection, its 1st joint about the length of the other 2 combined. First 

 pair of legs rather slender, through scarcely exceeding the length of the carapace, 

 basal joint fully as long as the remaining part of the leg, and coarsely spinulous 

 at the edges, the last 2 joints of about equal length and shorter than the an- 

 tepenultimate one; 2nd pair with the basal, ischial and meral joints coarsely 

 spinulous, antepenultimate joint rather slender, exceeding the length of the last 

 2 combined ; 3rd and 4th pairs slender, with the basal joint partly spinulous. 

 Uropoda not much elongated, rami exceeding half the length of the stem, the 

 inner one a little shorter than the outer, and having only 6 spinules inside (3 

 on the 1st. 2 on the 2nd, and 1 on the last joint), apical spine strong, mucroni- 

 form. Telson extending beyond the stem of the uropoda, and less narrowed 

 than usual, its proximal half being of nearly uniform width throughout, distal half 

 slightly tapered, and armed on each side with only 3 spinules, apical spinules 

 a little larger than the lateral. Colour whitish. Length amounting to 10 mm. 

 Adult male, as usual, much more slender than the female, with the 

 carapace less deep and more evenly vaulted above, having on each side behind, 

 a coarsely denticulated lateral keel, which however scarcely extends beyond the 

 middle ; anterior part of carapace fringed on each side with a row of densely 



s Crustacea. 



