482 



Gen. 1. Melphidippa, Boeck, 1870. 

 Syn. : Gammarus, Goes (part.) 



Body very slender and elongated, with the segments of metasome 



and iirosome produced dorsally and having their posterior edge dentated. 



Oephalon comparatively small, wthout any distinct rostrum, lateral corners 



well defined, lobular. Coxal plates very small, the 4 anterior pairs being 



scarcely deeper than the posterior ones; 4th pair not emarginated posteriorly; 



oth pair with the anterior lobe much deeper than the posterior. Eyes 



distinct, though having the visual elements imperfectly developed. Superior 



antennae very slender, with the peduncle more or less elongated, and the 



flagellum extremely narrow, accessory appendage well developed. Inferior 



antenniB but little shorter than the superior, and comparatively more strongly 



built, peduncle elongated and densely setous. Antennse in male scarcely 



differing from those in female except by the peduncles being densely clothed 



inside with delicate cilia. Anterior lip of the usual rounded form ; posterior 



lip with the inner lobes well defined. Mandibles strong, with the palp 



rather slender, and having the last joint well developed. Firist pair of maxillae 



witii the basal lobe comparatively broad, and edged with several ciliated 



setae. Second pair of maxillae having the lobes comparatively short and 



rounded at the tip, the outer one exceeding the inner in length Maxillipeds 



with the masticatory lobes a little longer than the basal ones, and edged 



interiorly with a restricted niimber of strong spines, at the tip with curved 



setae, palp much elongated and densely setous, last joint large and elliptical 



in form, dactylus elongated, .spiniform. Gnathopoda comparatively feeble in 



structure, and exactly alike in the two sexes, carpus large and more or' less 



laminarly expanded, propodos comparatively small and imperfectly subcheli- 



form ; the posterior ones genei'ally more slender than the anterior. The first 



2 pairs of pereiopoda very slender, and edged with long bristles, dactylus 



elongate and setous on both edges. The 3 posterior pairs of pereiopoda 



much elongated, and nearly of equal size, basal joint rather narrow, dactylus 



in the 2 posterior pairs recurved. Bi-anchial lamellae simple; inculpatory 



lamellae narrow. The 2 anterior pairs of uropoda with the rami naiTow 



linear and densely spinous, the outer one being much shorter than the inner; last 



pair very large, extending considerably beyond the others, basal part long 



and narrow, rami subequal and linear in form, being edged with spines. 



Telson small, oblong triangular, more or less deeply incised. 



