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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
pressed oval body, the broad caudal segment,
the de-
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.