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above-described genus Cylisticus. Yet there are some characters which seem to
distinguish all the forms belonging to this family, viz, the peculiar
the caudal segment and of the uropoda, as also the comparatively
structure of
short antennae
and legs. Moreover, Mr. B.-Lund has stated that the young leave their mother
in a more advanced stage of development than in other Oniscoida, having all
the 7 segments of the mesosome well defined. According to the same author, no
marsupial pouch is formed in the female. But this may be less correct,
have found in one specimen of Armadillidium pictum distinctly [developed incu-
batory plates. Mr. B.-Lund refers to this family 8 different genera, and 2 more
are added by Mr. Dollfus, increasing the number to 10 in all. Of these, only a
single genus is represented in the fauna of Northern Europe.
Gen. Armadillidium, Brandt, 1830.
I
as I
Generic Characters. Body oblong or elliptical in form, very convex, and
capable of being rolled up into a perfect ball. Cephalon with the front distinctly
marginate, lateral lobes rounded, and sharply defined at the base. Epistome ver-
tical, forming above a triangular shield, advancing more or less beyond the frontal
edge. Side-plates of 1st segment of mesosome large, securiform,
not incised
behind. Metasome semicircular, with the edges continuous throughout; last seg-
ment lamellar, quadrangular or triangular in form, not extending beyond the
limits of the epimeral plates of the penultimate segment. Eyes distinct, lateral.
Antennulse with the terminal joint but little produced. Antennae, as a rule, not
attaining half the length of the body, penultimate peduncular joint scarcely longer
than the 2nd ; flagellum biarticulate. Opercular plates of only the first 2 pairs
of pleopoda with air-cavities. Uropoda very short, with the basal part broad,
lamellar, outer ramus spatulate, inner narrow, cylindric.
Remarks.- This genus, established by Brandt, is easily distinguished
from Cubans (Armadillo), with which it was formerly confounded, by the non-
incision of the anterior side-plates of the mesosome, and by the broad, spatulate
form of the outer ramus of the uropoda. It comprises numerous species chiefly
from southern Europe, amounting, according to B.-Lund, to more than 30 in all.
Of these, only 4 species are represented in the fauna of northern Europe, and
will be described below.