download pdf

189
1. Armadillidium vulgare, Latr.
(PI. LXXX1I.)
Armadillo vulgaris, Latreille, Hist. Crust. Vol. VII, p. 48.
Syn: Armadillo pilularis, Say.
trivialis, Koch.
ater, Schnitzler,
uariegatus, Latr.
maculatus, Risso.
pustulosus, Desm.
Armadillidium commutation, Brandt & Ratzeb.
Specific Characters. Body oblong oval, more than twice as long as it
is broad, side-contours sub-parallel, dorsal face strongly vaulted and perfectly
smooth. Cephalon, seen dorsally, broadly quadrangular, transversely truncated
in front, lateral lobes comparatively small, rounded. Side-plates of 1st segment
of mesosome with the posterior corner acute. Metosome broad, semicircular,
scarcely occupying
more than l
/5 of the length of the body; last segment much
shorter than it is broad at the base, and slightly tapering distally. tip transversely
truncated. Antenna? very short, scarcely exceeding in length Y* of the body,
flagellum about the length of the last peduncular joint, and having its 1st arti-
culation somewhat shorter than the 2nd. Last pair of legs with the ischial joint
rather large, equalling in length the succeeding part of the leg. Copulative ap-
pendages of 1st pair of pleopoda in male with the tips slightly divergent; oper-
cular plate of 2nd pair rather produced, but scarcely curved outwards at the tip.
Uropoda with the outer ramus much shorter than the basal part, and very broad,
its distal edge being continuous with the last segment. Colour of dorsal face
somewhat variable, sometimes uniformly dark grey or nearly black, sometimes
variegated with lighter patches generally arranged on the mesosome in 3 longi-
tudinal rows, one median and 2 lateral; between them, moreover, on each segment
is a group of more or less distinct flexuous stripes. Length attaining 14 mm.
Remarks. This is the first described form of the family Armadilli-
diidoBj and it is even very probable that the Oniscus armadillo of Linneus may
refer to this species. It may be recognised from the other known species espe-
cially by the form of the cephalon and the last segment of the metasome, as
also by the very broad spatulate form of the outer ramus of the uropoda.
Occurrence.- The only record of the occurrence of this widely distributed
species in Norway is in a short note of Dr. Aug. Hansson, who states its
occurrence at Femsjo near Fredrikshald. I cannot, however, doubt that, on a
closer investigation, it will be found to exist in many other parts of the country,