321 



and scarcely reaching beyond the middle of the basal joint of the superior 

 antennae, lateral corners obtusely rounded off at the tip. First pair of coxal 

 plates much expanded in their outer part, distal edge straight, anterior cor- 

 ner distinctly angular ; the succeeding pairs nearly as in S. haplochelcs. Eyes 

 comparatively small, rounded, with only few viaual elements, pigment light red 

 with a whitish coating. Superior antennae about the length of the cephalon 

 and the first 4 segments of mesosome combined, 2nd joint of the peduncle fully 

 as long as the 1st, flagellum considerably shorter than the peduncle, and com- 

 ]iosed of 6 aiticulations only. Inferior antennae (in female) much shorter than 

 the superior, flagellum scarcely attaining the length of the peduncle. Anterior 

 gnathopoda somewhat less powerful than in S. haplocheles, and more resembling 

 those in S. hrevicarpum, propodos about twice as long as it is broad and oval 

 in form, palm but slightly arcuate and, as in the other species, having the 

 edge divided into several coarse denticles, carpal lobe somewhat less produced. 

 Posterior gnathopoda more slender than in S. hrevicarpum, but not nearly so mtich 

 elongated as in S. haplocheles, propodos rather narrow and gradually tapering 

 distally, chela occupying about Ve of its length. Pereiopoda nearly as in the 

 last-named species, except that the propodal joint of the 2 anterior pairs is 

 somewhat larger, and about the length of the carpal joint. Telson oval in 

 form, considerably longer than it is broad, tip transversely truncated. Body 

 pellucid, whitish, without any pigmentary ornament. Length of adult 

 female 4 mm. 



Bemarhs. — The present new species is somewhat intermediate in cha- 

 racter between the 2 above-described species. It agrees with S. haplocheles in 

 its outward aspect and the very pellucid and pigment-less body, but differs 

 in the form of the rostrum, in the less powerful anterior gnathopoda, and 

 the less slender posterior ones. In the latter characteristic, it comes 

 somewhat nearer to S. hrevicarpum.. 



Occurrence. — I detected this species last summer in the Trondhjems- 

 ijord, at Redbjerget, where some specimens were collected from a very con- 

 siderable depth, amounting to 400 fathoms, in company with other true 

 deep-water Amphipoda. 



Gen. S Halicreion, Boeck, 1870. 



Outward aspect much as in the genus Monoculodcu. Cephalon having the 

 frontal part rather produced, and terminating with an acuminate rostrum. 



41 — Crustacea. 



