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112
Paramunna bilobata,
(PI. XLVII, fig. 1.)
G. 0. Sars.
Paramunna bilobata, G. 0. Sars, Beretning om en i Sommeren 18H5 foretagen zool. Keise ved
Kysterne af Christianias og Christiansands Stifter, p. 31.
Specific Characters. Body oval in form, scarcely twice as long as it is broad,
with the segments very sharply marked off from each other. Cephalon rather broad,
deeply incised anteriorly in the middle, and forming on each side of the incision an
obtusely truncated lobe finely denticulated at the tip ; ocular processes
greatly projecting. Lateral parts of the 4 anterior segments
conical and
of mesosome trun-
cated at the tip; those of the 3 posterior acuminate and projecting laterally.
Caudal segment about half as long as the mesosome, rounded cordiform, lateral
edges rather bulging in front, and each armed with a regular
row of about 12
strong serrations increasing in size posteriorly, outer part of the segment obtusely
conic and smooth. Eyes well developed, and placed on the tips
of the ocular
processes. Superior antennae projecting laterally between the cephalic lobes and
the ocular processes, and equalling in length about half the breadth of the head,
the first 2 joints of the peduncle rather large, subequal, 3rd joint extremely small,
flagellum nearly as long as the peduncle, and composed of 3 articulations, the
last carrying a single long apical filament. Inferior antennee extending beyond
the superior, and nearly twice as long, flagellum much shorter than the pe-
duncle, and 7-articulate. 1st pair of legs very strongly built, with the joints con-
siderably expanded, carpus rather broad, and armed inside with 3 strong spines,
propodos about the size of the carpus, and oval in form, dactylus strong,
secondary tooth inside. Uropoda issuing just behind the serrated part
with a
of the
lateral edges of the caudal segment, rami very unequal, the outer one being ex-
tremely small. Colour bright red. Length of adult female scarcely exceeding 1 mm.
Remarks. This dwarfed Isopod may be easily recognized
from the other
Munnidce by its rather regular oblong oval body, the peculiar form of the cepha-
lon, and the shape and armature of the caudal segment. The distinct, peduncu-
lated eyes distinguish it at once from the species of the nearly-allied genera,
Leptaspidia, Neasellus and Pleurogonium.
Occurrence. I have met with this form occasionally in several places of
the Norwegian coast, from the Christiania Fjord up
to the Lofoten Islands. It
generally occurs in moderate depths ranging from 20 to 40 fathoms, among Alga?
and Hydroidse, more rarely in greater depths amounting to 100 fathoms. Owing
to its small size,
it may easily be overlooked, or taken for some Copepods of
the Scntellidian group. Out of Norway it has not yet
been recorded.