415 



structure of the gnathopotla. In both these respects it would seem to approacli 

 nearer to the family Gammaridce and especially to the genus Cheirocrafus of 

 Norman. Only two of the genera belonging to the present family are represented 

 in the fauna of Norway. 



Gen. 1. EusirUS, Kroyer, 1845. 



Body compressed and more or less distinctly carinated dorsally, some 

 of the segments being produced to posteriorly-pointing, dorsal projections. 

 Cephalon with a rather small rostral prominence, lateral corners short and 

 broad. Coxal plates of moderate size, 1st pair broadly expanded distally, 4th 

 pair much the largest, and distinctly emarginated posteriorly in their upper 

 part; the 2 succeeding pairs not nearly so deep as the preceding ones, and 

 having the anterior lobe scarcely larger than the posterior. Epimeral plates 

 of metasome rather large, those of last pair serrated posteriorly, and not at 

 all produced at the lateral corners. Eyes distinct, though having the visual 

 elements imperfectly developed. Superior antennae, as a nile, longer than 

 the inferior, and with the last joint of the peduncle short and very movably 

 articulated to the preceding joint, being encompassed at the base by 2 more 

 or less strongly dentated lappets issuing from the end of the former, acces- 

 sory appendage forming a small linear joint lying inside the base of the 

 flagellum. Inferior antennae not modified in the male. Anterior lip rounded; 

 posterior one witli distinct, though small inner lobes. Mandibles rather strong, 

 cutting edge but slightly dentated, palp elongated and slender, with the 

 terminal joint full}' as long as the other 2 combined, and very narrow. First 

 pair of maxillae comparatively small, with the palp but little expanded distally 

 and the basal lobe unisetose. Second pair of maxillae with both lobes short 

 and rounded at the tip, the inner one considerably broader than the outer. 

 Maxillipeds rather large, basal lobes partly coalesced, masticatory lobes of 

 moderate size, and setous along the inner edge and the apex, palp very robust, 

 with the last joint strongly developed, and the dactylus unguiform. Gnathopoda 

 subequal both in size and structure, and of rather peculiar structure, the 

 carpus being nnich elongated and produced inferiorly, at the base, to a setous 

 lobe, its outer part extremely narrow and attenuated, propodos very broad, 

 subquadrangular or transversely elliptical in shape, and affixed to the carpus 

 at the upper posterior corner, palm nearly transverse, and defined below by 

 on obtuse projection armed with several strong spines, its edge sharpened 

 and minutely setous, dactylus slender and curved. The 2 anterior pairs of 



