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in Trichoniscus. Oral parts likewise rather similar, except that the terminal part
of the maxillipeds is obscurely 5-articulate, and the epignath simple, lanceolate.
Legs short and thick, scarcely at all increasing in length posteriorly. First pair
of pleopoda in female very small and rudimentary; those in male well developed,
with the inner ramus strongly produced, Inarticulate, terminal joint spiniform;
inner ramus of 2nd pair in male likewise much produced, triarticulate, last joint
narrow styliform. Uropoda with the inner ramus originating inside a broad ex-
pansion of the basal part, and terminating, as in the genus Trichoniscoides. in a
single slender spine.
Remarks. This genus, established in the year 1860 by School, approaches,
in the anatomical details, very near to Trichoniscus, or perhaps still nearer to Tri-
choniscoides, with which it agrees in the simple structure of the eyes. It is,
however, distinguished from both these genera by the peculiar sculpturing
of the
dorsal face, and by the lamellaiiy expanded lateral parts of the segments, causing
the metasome to be less abruptly contracted than in the above-named genera.
In the
latter character it agrees with the genus Scyphacella of Smith, which may perhaps
turn out to be identical with it. We know of 2 distinct European species, both
of which belong to the fauna of Norway, and will be described below.
l. Haplophthalmus Mengii, (Zaddach).
(PI. LXXIV, fig. 1.)
Itca Mengii, Zaddach, Synops. Crust. Pruss. p. 16.
Syn: Haplophthalmm elegans, ScliObl.
Specific Characters.- Body oblong oval, somewhat attenuated behind, with
the dorsal face moderately convex. Cephalon rather large,
with the front trian-
gularly produced and tipped with several small denticles, lateral lobes compara-
tively broad, rounded quadrangular, dorsal face divided in the middle by a
transversal groove, its posterior part rather convex, and provided with several
curved longitudinal ribs. Dorsal face of mesosome sculptured with 6 very distinct
equidistant longitudinal ribs finely crenulated on the edge,
the outermost rib, how-
ever, on the 1st and last segments, being irregularly interrupted; lateral plates
subtruncate at the end, and having at their base a less conspicuous rib, 1st
and last pairs somewhat broader than the others. Metasome scarcely attaining
Y4 of the length of the body, 3rd segment with 2 very prominent juxtaposed
ribs dorsally; last segment narrowly truncate at the tip. Antennulse with the
basal joint rather broad and curved, terminal joint with only 4 sensory filaments.
Antennse scarcely attaining '/4 of the length of the body, fiagellum shorter than