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52
Praniza might be the female of Anceus. Indeed, the 3 forms are so widely diffe-
rent both in their general appearance, and in the structure of some of the appen-
dages, that one ma} 7 be easily led to suppose that they belonged to as many distinct
genera. The communications of M. Hesse therefore at first occasioned no little
discussion among Corcinologists, and the correctness of his observations relating
to the transformation of Praniza, into Ancen*. \v;is even simply denied 1
);
subsequent investigations have, on the whole, fully
but
confirmed his statements about
the peculiar trimorphism occurring in tins genus. A rather large number of
species, amounting to more than 20 in all, have been recorded from different parts
of the Oceans; but the far greater part of them have been only
described from
male specimens. To the fauna of Norway belong 4 species, to be described below.
l. Gnathia maxillaris (Mont,).
(PL XXI, PI. XXII, fig. 1.)
Cancer nHt.rUh'tris, Montague, Trans. Linn. Soc., Vol. VII, p. 65, PI. 6, fig. 2.
Syn: Anceus maxittaris, Lamk. cf.
Praniza coeruleata, Desm. (Larva).
.,
Anceus oxyurceus, Lilljeb. cf-
Praniza Edwardii, Sp. Bate 9-
? Anceus iiHiiitirni us. Hesse.
Specific Characters. Mali'. Body almost elavate in shape, being gradually
expanded in front, with the anterior part of inesosorne divided from the posterior
by a rather deep constriction. Cephalosome transversely quadrate, deeply ex-
cavated above in its anterior part, dorsal face smooth and distinctly areolated, supra-
ocular denticle comparatively small. Posterior division of mesosome narrower
than the anterior, dorsal face quite smooth, without any areolation. Eyes well
developed. Mandibles rather large, broadly lanceolate, with a slight obtuse notch
outside, inner edge bulging in the middle, and obscurely crenulated in its outer
part, tip scarcely incurved. Pereiopoda
joints. Pleopoda well developed, natatory. Uropoda
with scattered tubercles inside the outer
with the rami foliaceoiis.
and fringed with long ciliated setie. Terminal segment of metasome triangular,
gradually tapering to a point carrying
2 slender bristles. Sexual tubercle small.
but little prominent. Colour yellowish brown, with the areohe of the head whitish,
defined by narrow dark brovMi grooves. Female: Body oblong fusiform,
with the 2
') It may be noted that tin; strange controversy which at first took place between
M. Hesse and Mr. Sp. Bate, was merely due to the fact that the latter author regarded the
adult female as a Praniza, whereas M. Hesse more correctly named it p, female