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has advanced the opinion that another species, established by the same author from
a fragment of a specimen, may also require to be transferred to a new genus.
Gen. GnatMa, Leach, 1814.
Syn: Anceus, Eis.su (male).
,. Praniza, Latr. (larva).
Generic Characters. Body in male subdepressed,
and more or less di-
lated in front, with the cephalon very large, subquadrangular, and flattened ante-
riorly, inesosome divided by a more or less conspicuous constriction into 2 sections,
the anterior comprising 2, the posterior 3 well-developed segments, the foremost
rudimentary segment being consolidated with the head, the hindmost received
between the projecting lateral parts of the 5th segment. Body in female and
larva more or less fusiform, with the cephalon rather small, and some of the
segments of mesosome fused together. Metasome in both sexes, as also in the
larva, much narrower than the mesosome, sublinear in form. Eyes, when present,
placed laterally. Antennas comparatively short and subequal in length, both pairs
with distinctly denned flagella. Mandibles in male of different form ind the
different species, more or less flattened, forceps-like. Maxillipeds without epignaths,
masticatory lobe simple, palp consisting of 4 flattened joints fringed
outside with
strong plumose seta.1
; those in female much smaller, but of a similar structure.
Oral parts in the larva combined into a rostrum-like cone projecting in front, and
in a great measure styliform. Gnathopoda in male forming a pair of very large
curved plates arching over the lower face of the cephalon, and terminating
small apical joint; those in female much smaller and more pediform, being divided
into 3 or 4 joints, and having at the base a thin lamella. IVreiopoda subeqiial and
of normal structure. Pleopoda with the rami uni-articulate, tipped with long seta 1
or quite, naked (in the adult animal). Uropoda with both rami lamelliform, snhe-
qual, and edged with slender bristles.
in a
Remarks. This genus was established as early as in the year 1814 by
Leach under the above name, which, according to the rules of priority,
must be
preferred to the more generally used terms Anceus (the male) and /'ranita (the
larva). To the French zoologist, E. Hesse, is due the merit of first having made
out precisely the true relationship between the male, female, and larva, which had
not formerly been fully recognized, though Leach had already conjectured, that the
,