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Fam. 4. Desmosomidae.
Characters. Body more or less elongated, with the segments, as a rule,
sharply marked off from each other, the 3 posterior segments of mesosome gener-
ally defined from the 4 anterior by a well-marked constriction. Cephalon emarginated
on each side for the insertion of the antenna;, frontal part more or less
produced. Caudal segment generally rounded at the tip. Eyes wholly absent.
Superior antennae, as a rule, small, and placed wide apart. Inferior antennae not
particularly elongated,
sometimes different in the 2 sexes. Mandibles with or
without palps. Maxillipeds always lamellar, with the joints of the palp more or
less expanded. 1st pair of legs generally unlike the others, prehensile or very
slender. The 3 posterior pairs of legs in some cases natatory, with the outer
joints flattened, but never, as in the Munnopsidce, edged
poda generally small,
bi- or uni-ramous.
with ciliated seta;. Uro-
Remarks. The present family is somewhat intermediate in character
between the Icmiridos and Munnopsidce, some of the forms resembling the former,
others the latter family. I have, however, thought it advisable to keep it apart
from both of them. All the known forms are blind, and generally have the body
narrow and elongated, with the segments, as a rule, very sharply marked off from
ea'-li other, so as to exhibit a more or less moniliform shape. The family com-
prises as yet 6 genera, all of which are represented in the fauna of Norway.
Gen. 1. NannOniSCUS, G. O. Salts, 1S69.
Generic 0/um/rfox Body distinctly depressed, with the segments rather
densely crowded together, and lamellarly expanded laterally. Cephalon compara-
tively large, with the frontal part considerably produced. Caudal segment like-
wise larger than usual, semi-oval. Superior antemue extremely small,
with the
peduncle apparently only consisting of 2 joints, tiagellum rudimentary, and carrying
outside a single, enormously developed olfactory papilla. Inferior antenme of
moderate size, with the peduncle 6-articulate, its 3rd joint being produced outside
to a strong, anteriorly pointing spine. Mandibles with the molar expansion rather
slight, conical, and tipped by a fascicle of slender bristles; palp distinct,
3 -arti-
culate, though not very large. Maxillipeds pronouncedly lamellar, penultimate
joint of the palp produced at the end inside to a digitiform process; epignath