ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
365 
two equal halves. This groove is, in its turn, cut perpendicularly to its 
length by parallel incisions, which divide it into twenty-one hands, at 
the outer margin of which a bud soon appears. This bud is the first 
indication of the appendages; at first, all the bands and all the buds are 
exactly similar, with the exception of the foremost, which is provided 
with cephalic discs. 
Soon differentiations are seen in the buds, and three groups can be 
distinguished ; the cephalic is composed of seven pairs of buds ; the 
thoracic has seven ; and the ventral has the last seven. As the author 
regards the cephalic plates as the first somite, and as they bear the 
ocular cones, he looks on them as oculiferous limbs which remain 
rudimentary. 
The egg has an outer membrane or chorion, below which there is 
a second and much more delicate layer or deutovum ; below this there 
is what appears to be an amniotic sac, but it does not completely 
envelope the embryo ; it is only developed on the dorsal surface, and it 
is this which has been taken by embryologists for a special organ. 
Development of Amphipoda.* — Madame C. Wagner devotes the fifth 
memoir on the development of Amphipoda to Melita palmata. In many 
points of external development the history is the same as that of 
Gammarus and Caprella, but this is not the case as to the development of 
many of the internal organs. Though most of the ectodermal cells are 
much flattened there is in the middle of the back a group of very large 
cells, which represents the foundation of the dorsal organ ; the cells of 
this group are at first amoeboid in form, but later on they elongate, and 
in transverse section are seen to have a fan-shaped disposition. Each 
ganglion of the ventral chain is developed independently and there is no 
fusion to form a chain until after the complete development of the central 
dotted substance ; it is for this reason that the commissures are only 
formed of the central nervous mass. 
The endodermal cells early form two symmetrical bands on each side 
of the middle line of the embryo ; towards the oral pole, however, and 
a little below the equator of the egg the two bands seem to be fused ; the 
endodermal elements multiply with great rapidity, and at either end there 
is formed a cul-de-sac ; these represent the foundations of the two 
hepatic sacs. 
Antennary Gland of Orchestiidse.f — M. J. Bonnier remarks that the 
sole justification for separating the Orchestiidse from the rest of the 
Gammaridea, and calling them Saltatoria as opposed to Natatoria, is the 
absence of the antennary gland. This organ, however, is present, and 
G. O. Sars is justified in his suggestion that the Orchestiidfe should be 
considered as merely a subdivision of the Gammaridea. 
Reproduction of Cirripedia.J — M. A. Gruvil finds that the ordinary 
method of fecundation in Cirripedes is reciprocal ; when this is impos- 
sible there may be self-fecundation. There is no true copulation, but 
merely an apposition of the sexes and deposit of the sperm near the 
oviducts. In Pullicipcs there appears to be merely self-fecundation. 
* Bull. Soc. Imp. Moscou, 1891 (1892) pp. 401-9 (2 pis.). 
t Comptes Rendus, cxiii. (1891) pp. 808-10. 
X Tom. cit., pp. 706-8. 
