GENERAL MORPHOLOGY. 
Crust. 7 
sex ; the vasa deferentia are provided with small cleft-like openings out- 
side, and these are connected by a small channel placed on the lateral 
plates, with the true intromittent organs (appendages of the second 
abdominal segment). Copulation takes place in April and May, and the 
female orifices are closed by the next moult, before the spermatozoids 
have proceeded from the receptaculum seminis to the oviduct ; the 
fecundated eggs break afterwards through the faint walls of the oviduct 
into the abdominal cavity, and by a special median cleft to the outside 
botwoen the brooding lamella), wliero thoy receive nourishment from four 
peg-like prolongations of the abdominal integument on the second, third, 
fourth, and fifth segments, which have been very properly termed 
cotyledons by Treviranus. The breeding lamellae are formed earlier 
beneath the skin, and come free at a subsequent moult. Fecundation 
in spring suffices for the summer, and before winter the female orifices are 
reopened by a further moult. There are, accordingly, two sexual periods 
each year in the females, one with open orifices in winter and spring, 
and one with closed orifices and developed cotyledons, destined for the 
further development of the eggs, in summer. Z. ges. Naturw. (4) ii. 
pp. 447-474, pi. v. 
De la Yalette describes the genital organs of both sexes of Oniscu-s 
murarius (Guv.) [ asellus (L.)] and some species of Porcellio, the struc- 
ture of the eggs, and the formation of the spermatozoids ; he mentions 
former authors on this subject, and in the main confirms the views of 
J. Schobl [Zool. Rec. xvi. Crust, p. 38], adding that the eggs are not 
ejected by the so-called oviduct of authors, which is to be called vagina, 
but that they become free by the spontaneous destruction of that part 
of the ovary which contains the mature eggs. “ De Isopodibus,” Pro- 
gramm of the University of Bonn, Aug. 1883, with 2 pis. 
On Spermatogenesis in the Ediophthalm Crustacea ; G. Hermann, C.R. 
xcvii. pp. 1009-1012. 
5 . Development. 
Abstract of Brooks’s paper on the metamorphosis of Peneus in J. 
Hopkins Univ. Circ. No. 19, 1882, and Ann. N. H. (5) xi. pp 147-149. 
W. Faxon makes some critical remarks on this paper ; Am. Nat. xvii. 
p. 554. 
E. A. Birge describes the development of Panopceus sayi (Smith), 
distinguishing and figuring the following stages : — 
First Zoea, still in larval skin. 
Second Zoea, moulted from larval skin, four swimming hairs, long 
dorsal and frontal spines, long antennae. 
Third Zoea, six swimming hairs, first appearance of abdominal legs 
under skin, long spine on fifth abdominal segment. 
Fourth (or later) Zoea, eight or more swimming hairs, external ab- 
dominal legs, spines on anterior abdominal segments. 
Last Zoea, tw r elve or more swimming hairs, divided telson, mandibu- 
lar palpus. 
First Megalops, immediately after moult from last Zoea, all long 
