download pdf

139
Gen. 3. EehmOZOne, G. 0. Sars, n.
Syn: Ih/amclnia, G. 0. Sars (pnvt).
Generic Characters. Body somewhat resembling in shape that in the genus
Ilyarachna, but comparatively shorter and thicker, with the anterior segments of
mesosome strongly spinous, the 3 posterior segments short and broad. Caudal
segment distinctly notched on each side, at some distance from the tip. Antennae
about as in Ilyarachna. Mandibles very large and without a trace of palps.
Ambulatory legs resembling those in the genus Ilyarachna; natatory legs,
on the
other hand, far less fully developed, with the outer joints but slightly expanded.
Uropoda with 2 distinct rami issuing from the outer side of the large, lamellar
basal part.
Remarks, This new genus is founded upon the form previously described
by the present author as Ilyarachna coronata. On a closer anatomical examin-
ation of this form, I have found it to differ in some particulars rather markedly
from the 3 above-described species, so that it ought more properly to be regarded
as the type of a nearly-allied genus. Among these differences may
be named the
absolute absence of mandibular palps, and the biramous character of the uropoda.
The genus comprises as yet but a single species.
Echinozone coronata,
(PI. LXI, fig. 2.)
G. 0. Sars.
l
Ilyarachna coronata, G. O. Sars, Nye Dybvamlscrus aceer fra Lofuten. Clir. Vid. Selsk. Forlidl.
1869, p. 168.
Specific Characters. Body very short and compact, scarcely
twice as long as it is broad. Cephalon with the dorsal face strongly
perfectly smooth, lateral parts obliquely expanded. Anterior edge
more than
vaulted and
of the first 4
segments of mesosome considerably raised, and divided into 6 8 coarse spiniform
projections, between which are as many very small denticles, lateral parts
segment simple, those of the 3 succeeding segments each produced
of 1st
into 2 acute
lappets. The 3 posterior segments of mesosome comparatively short, and, com-
bined, not nearly attaining the length of the anterior division,
dorsal face some-
what uneven, anterior edge of 1st segment slightly denticulated. Caudal segment
scarcely longer than it is broad at the base, lateral edges minutely setous, and
exhibiting, at some distance from the tip, a very
distinct notch denned in front
by a dentiform projection, tip acutely produced. Superior antenna? not reaching
to the middle of the antepenultimate peduncular joint of the inferior ones, basal
joint of moderate size and without any denticles, nagellum 10-articulate. Inferior