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158
Remarks. This genus, established by Brandt, is chiefly distinguished from
Ligia, by the abruptly contracted metasome, the less rudimentary state of the an-
tennulffi, and the peculiar structure of the uropoda. The genus Zla of Koch is
identical with the present genus. Several species have been described, amounting,
according to Mr. Budde-Lund, to 8 in all. Only one species belongs
Scandinavian fauna, and it will be described below.
Ligidium hypnorum (Cuv.).
(PI. LXXI.)
Oniscus liypnornm, Gtivier, Journ. d'hist. nat. Vol. II, p. 19, pi. 26, figs. 3 5.
Syn : Oniscus agilis, Persoon
Ligia liypnorum, Bosc.
Zia agilis, Koch
,. Ligidium Personii, Zadclach
Zia Soundersii, Stebbing
Ligidium agile, Norman.
to the
e Characters. Body oblong oval, greatest width not attaining half
the length, dorsal face rather convex, and perfectly smooth and shining. Cephalon
of moderate size, and evenly rounded in front, dorsal face transversely grooved
behind the eyes. Lateral parts of the 3 anterior segments
slightly prominent; those of the 4 posterior segments somewhat larger,
of mesosome but
and ter-
minating behind in obtuse points. Metasome scarcely exceeding in length 1
/s of
the mesosome, and much narrower, with the epimeral plates small and apprcssed;
last segment obtusely rounded at the tip, with a slight angle on each side. Eyes
very large, oval, extending down Ihe sides of the cephalon. Antennulse with the
1st joint rather thick, 2nd longer but much narrower, both armed at the tip in-
side with 3 rather long diverging spines, last joint very small, narrow cylindric.
Antennae rather slender, though not nearly attaining half the length of the body,
flagellum somewhat shorter than the peduncle, and composed of about 11 arti-
culations, the last tipped with a dense bunch of delicate hair-like bristles. Legs
armed with scattered slender spines, propodal joint very narrow and elongated.
dactvlus simple. Inner plate of 1st pair of pleopoda in male slightly produced
at the tip, and provided with 4 apical bristles. Uropoda scarcely exceeding half
the length of the metasome, inner projection of the basal part occupying
about halt' its length, outer ramus gradually tapering distally and carrying
"ii the tip 3 short bristles, inner ramus very narrow, linear, not extending
to the tip of the outer, apical bristles nearly as long as the ramus. Colour
of dorsal face light fuscous, variegated with irregular dark patches, which on each
side, at the base of the lateral plates of mesosome, form a nearly continuous
longitudinal band. Length of adult female 9 mm.