144 



Gen. 6. EliryCOpe, G. 0. Sars, 1863. 



Generic Characters. Body rather compact and distinctly depressed, more or 

 less oval in outline, with the 2 divisions of mesosome less sharply marked off from each 

 other than in the preceding genera. Cephalon of moderate size, deeply emarg- 

 inated on each side for the insertion of the antenna?, frontal part more or less 

 projecting. The 4 anterior segments of mesosome comparatively, short, subequal, 

 transversely excavated dorsally; the 3 posterior segments very large and broad, 

 with the dorsal face smooth and convex. Caudal segment semi-oval, obtusely 

 rounded at the tip. Superior antennae with the basal joint large and massive, 

 flagellum multiarticulate. Inferior antennae very slender and elongated. Mandibles 

 normally developed, with the cutting edge divided into strong teeth, and the molar 

 expansion rather thick, palp comparatively large, with the terminal joint lamellar 

 and much curved. Maxillae normal. Maxillipeds pronouncedly lamellar, penulti- 

 mate joint of the palp produced at the end inside to a digitiform lappet, epignath 

 large, and of different form in the different species. 1st pair of legs slender, but 

 shorter than the 3 succeeding pairs, which are subequal and generally very much 

 elongated, terminating in a slender claw. Natatory legs very fully developed and 

 all of same structure, carpal and propodal joints strongly expanded, foliaceous, 

 and densely edged with plumose setae, dactylus distinct. Uropoda comparatively 

 small, biramous, basal part net lamellarly expanded, rami linear. 



Remark*. This genus, established by the present author in the year 

 1863, is perhaps the most typical of the Munnopsidae, in so far as the natatory 

 legs- are more powerfully developed than in any of the other genera. The swim- 

 ming motion of the animal is accordingly extremely rapid and of longer duration 

 than in the other Munnopsidce. The genus is chiefly characterised by the de- 

 pressed oval body, the broad caudal segment, the uniform structure both of the 

 ambulatory and natatory legs, and finally, by the structure of the uropoda. 

 Rather a large number of species have been described in recent times, from differ- 

 ent parts of the Oceans, amounting to 22 in all. From the Challenger Expedi- 

 tion alone, no less than 13 species have been recorded by Mr. Fr. Beddard; but 

 some of these ought perhaps more properly to be separated as types of nearly- 

 allied genera. To the fauna of Norway belong 8 species, to be described below. 



