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11
than the superior, flagellum short, and, as a rule, only Inarticulate. Mandibles
of various structure in the several genera, but always without palps. Anterior
maxilla? with only a single slender masticatory lobe; posterior ones quite
rudimentary, forming simple rounded lobes. Maxillipeds coalesced at the base,
epignath generally narrow, falciform. Chelipeds, as a rule, strongly
built and
closely applied to the oral area, issuing from the posterior part of the cephalo-
sonie with a broad base, carpus generally broad and compressed, hand some-
times rather dissimilar in the two sexes. Second pair of legs not very different
from the succeeding ones, being rather small and ambulatory in character. Pleo-
poda, as a rule, very small, with the rami lamelliform and incurved, sometimes
in female rudimentary or quite wanting. Uropoda not much elongated, simple
or biramous.
Remarks. - - This family may be easily distinguished from the preceding
one, both as regards the outward appearance of the body,
and the structure of
the several appendages. It comprises rather a large number of genera, amounting
to about 1 5 in all. These genera are chieliy characterised by the structure of the
mandibles, partly also by that of the superior antenna?, the legs
and the several
appendages of the metasome. As to habits, the greater part of the species
perhaps all seem to be tubicolar in character, constructing for themselves abodes
of mud, into which they may wholly withdraw their bodies. They all, moreover,
exhibit this peculiarity, namely, that on reaching the surface of the water, they
remain floating, without being able to reimmerge their bodies, whereby the dis-
covery of the generally very small and inconspicuous specimens is essentially
facilitated. On placing some muddy clay taken from greater depths,
low vessel, and stirring up the mud, they will very soon appear floating
surface like small white pins, and may easily be taken up
in a shal-
on the
for a closer examina-
tion. To the Norwegian fauna belong 11 different genera, to be described below.
Generic Characters.
Gen. 1. TanalS, M.-Edw., 1829.
- -
Syn.
Crossurus Eatlike.
Body not much elongated, but with the cephalosome
rather tumid and provided with distinctly defined ocular lobes. Metasome only
composed of 5 segments. Eyes well developed. Superior
antenna? of similar
structure in the two sexes, 3-articulate, with a very small knob-like terminal