61 



1 1 . Diastyloides serrata, G. 0. Sars. 



(I'l. XLV.) 

 I Kant i/lis sen-n/ii, (1. O. Sars. Om den uberrante Krebsdyrgmppe Cumacea, p. 44. 



Body moderately slender, with the anterior 

 division oval in form, and considerably vaulted dorsally. Carapace very large 

 more than twice as long as the exposed part of the trunk, and evenly arcuate 

 above, frontal lobe short and broad, ocular lobule almost obsolete, surface nearly 

 smooth throughout, though, on a closer examination, the upper part of the 

 branchial regions appears clothed with very small, anteriorly-curving denticles; 

 pseudorostral projection greatly produced, horizontal, tip acuminate and slightly 

 deflexed, subrostral corners obsolete, lower edges of carapace coarsely serrate 

 throughout their whole length. Last pedigerous segment with the lateral parts 

 scarcely produced behind, though terminating in an acute corner. Tail slender, 

 with the segments quite simple. Superior antennae with the peduncle not reaching 

 to the tip of the pseudorostral projection, its 1st joint somewhat shorter than 

 the other 2 combined. First pair of legs scarcely longer than the carapace, 

 basal joint not nearly attaining the length of the remaining part of the leg, and 

 strongly spinous on the lower edge, penultimate joint longer than the antepenulti- 

 mate, last joint comparatively short, not even attaining half the length of the 

 penultimate one; 2nd pair with the basal joint produced at the end below to a 

 strong spiniform projection, antepenultimate joint about the length of the last 2 

 combined; 3rd and 4th pairs rather slender and having the basal joint coarsely 

 denticulate behind. Uropoda with the rarni nearly equal in length, and not much 

 shorter than the stem, the inner one slender and attenuated, with the 1st joint 

 almost twice as long as the other 2 combined, spinules of the inner edge about 

 12 in number (9 on the 1st, 2 on the 2nd, and 1 on the last joint), apical 

 spine slender and well defined at the base. Telson comparatively short, scarcely 

 exceeding in length l /- A of the uropoda, its proximal part rather thick, distal part 

 but slightly tapered, and armed on each side with about 5 small spinules, apical 

 spines rather large and pointing straight behind. Colour whitish with a faint 

 yellowish tinge. Length 6 mm. 



Adult male very slender, with the anterior division far less tumid than 

 in the female, and but slightly vaulted above. Carapace perfectly smooth and 

 less deep than in female, pseudorostral projection somewhat shorter and more 

 horizontal. Last pedigerous segment with the lateral parts narrowly produced 

 behind. Tail very slender and having the segments unarmed. Antennae and 



