ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
187 
the lens. We can give an illustration only of how the classification 
is worked out : — 
Palp of the maxillipedes is free ; 
the margins of the last two joints 
are more or less setose, never 
with hooks. The lacinia of the 
third joint of the first maxilla at 
least towards the middle is rather 
broad. 
Cirolanidae, Corallanidae, 
Alcironidae. 
Palp of the maxillipedes sur- 
rounds a cone formed from the 
distal portions of the other mouth- 
parts; the intero-superior margin 
and apex are never setose, the 
apex and sometimes the intero- 
superior margin at least in the 
males and young females bear 
curved hooks. The lacinia of the 
third joint of the first maxilla is 
always narrow. 
Baryhrotidfe, iEgidae, 
Cymothoidae. 
Oviposition and Fertilization in Asellus aquaticus.* — Herr G. 
Leichmann finds that Rosenstadt is not right in thinking that the 
oviposition of the Asellina is exactly similar to that of the Oniscidae, as 
described by Schobl and Friedrich. The eedysis which takes place 
immediately after fertilization does not cause the disappearance of the 
genital orifices : they are merely hidden by the now developed brood- 
lamellae. The brood-plates appear very early as short delicate pro- 
cesses at the base of the first four pairs of legs. They do not arise as 
mere thickenings but are evaginations of the liypodermis, and con- 
sequently inclose a cavity which is in free communication with the body- 
cavity ; in the interior of the larger processes the hypodermis becomes 
converted' by numerous foldings into brood-lamellae. Fertilization is 
not effected, as Sars supposed, in the brood-space, but in the ovary ; 
before it is effected the middle part of the oviduct swells out into a large 
receptaculum seminis, into which the sperm* mass is received. After 
oviposition the oviducts shrink down again to their original form. 
Care of Young in Isopoda.f — Herr G. Leichmann makes a contri- 
bution to our knowledge of this subject by an account of his observations 
on Sphseroma rugi cauda ; the transparent embryos are not inclosed in 
the brood-cavity but in saccules with delicate membranes which lie in the 
interior of the body of the mother. 
Dimorphism of male Amphipoda.if — M. J. Bonnier records some 
observations on this subject. Some years since Fritz Muller described 
the dimorphic males of Orcliestia Darwini, and other cases have since 
been described ; these have been explained by Faxon, who points out 
that there is no true dimorphism, but rather a succession of forms, one 
of which is and the other of which is not adapted for copulation. 
M. Bonnier has been able to confirm the truth of this explanation by 
a study of Orchestia littorea and Bathyporeia pilosa. The presence of 
matured testes in the non-copulatory form of the former is not a sufficient 
argument against this explanation, for other Crustacea are known in 
* Zool. Anzeig., xiii. (1890) pp, 715-6. f T. c., pp. 688-91. 
f Comptes Rendus, cxi. (1890) pp. 987-9. 
