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increasing in length posteriorly. Opercular plates of the 2 anterior pairs of pleo-
poda with air-cavities, more rarely also those of 3rd or of all pairs. Copulative
organs of male nearly as in Porcellio. Uropoda rather produced,
structure to that in Porcellio.
and of a similar
Remarks. This genus established by Mr. Bndde-Lund, is nearly related
to Porcellio, though easily distinguishable from it by the smallness of the cephalic
lobes, the poor development of the side-plates of the mesosome, and the abruptly
contracted metasonie. The generic name refers to the fact, that the frontal edge of
the cephalon is nearly straight, not as in Porcellio produced in the middle. Mr.
Budde-Lund describes no less than 35 species of this genus, chiefly from the
southern part of Europe. Only a single species belongs to the fauna of Norway ;
it will be described below.
Metoponorthus pruinosus (Brandt).
(PI. LXXX, fig. 2.)
Porcellio pruinosus, Brandt, Consp. monogr. Crust. Isop. terrestr. p. 19, fig. 21.
Syn : Porcellio truncatus, M. Edw.
maculicornis, Kocli.
frontalis, Lereb.
Porcellionides flavo-vittatus, Miers.
Specific Characters. Body oblong, more than twice as long as it is broad,
dorsal face but slightly convex and nearly smooth, though, on a closer examina-
tion, exhibiting a very fine granulation. Cephalon transversely quadrangular, al-
most twice as broad as it is long, lateral lobes extremely small, frontal margin
straight. Side-plates of the 4 anterior segments of mesosome scarcely at all
projecting, those of the 3 posterior segments somewhat larger, with the posterior
corners obtusely acuminate. Metasonie not attaining 1
U of the length of the
body, and much narrower than the mesosome, epimeral plates
of the 2 anterior
segments concealed, those of 3rd to 5th segments comparatively small, recurved ;
last segment nearly twice as broad at the base as it is long, subtriangular, tip
pointed. Antennula? with the last joint scarcely longer
than the middle one.
Antennae very slender and elongated, exceeding half the length of the body,
flagellum somewhat shorter than the last peduncular joint, and having its prox-
imal articulation nearly twice as long as the distal one. Legs very slender,
minutely spinulose inside, propodal joint narrow, sublinear. Opercular plates of
only the 2 anterior pairs of pleopoda provided with air-cavities, and of somewhat
different shape in the two sexes. Uropoda with the outer ramus nearly twice as
long as the basal part, inner ramus extending scarcely to the middle of the