6 Grust. 
CRUSTACEA. 
position, and adds some particulars concerning the development of the 
spermatozoa; 1. c. pp. 254-256. Moseley persists in thinking the case 
very questionable, us the histological structure of the pretended testes is 
not described ; 1. c. pp. 310 & 311. [P. Mayer has since fully confirmed 
Bullar’s views, as will be seen in the Record for 1878.] 
W. J. SciiMANKEWiTSCii has continued and confirmed his researches 
upon the structural differences between specimens of the same species 
living in fresh or more or less saline water [c/. Zool. Rec. xii. pp. 228 
& 229] ; he has found these differences in the sensitive bristles of the 
antennae, the spines of the post-abdomen, and in general colour and size, 
in Daphnia rectirostris (Ley dig) and Cyclops brevicaudatus (Claus), 
Gfenerally the saltwater form is the less developed, nearer to the juvenile 
state ; one form can be arbitrarily changed into the other, by breeding in 
different water. In saline water, a species lives and multiplies at a low 
temperature, in which it would die if in fresh water. These observations 
were first made at the meeting of Russian naturalists at Kiew, Aug. 
1871 (abstract in Z. wiss, Zool. xxii. 1872), and fully published in Russian 
in the publications of the New Russian Society of Naturalists, iii. part 2, 
in 1875; and in German in Z. wiss. Zool. xxix. pp. 429-494. See also 
A rtemia^ Daphnia^ and Cyclops in the special part, infra. 
Embryology. 
P. Mayer has observed the first development of several Decapoda^ 
chiefly of Eupagurus prideauxi (Leach), at Naples, and describes it 
minutely. The chief results are as follows: — The egg is originally a 
normal coll, originating from the epithelium of the ovary, but afterwards 
modified by deposition of deutoplasm within it and disappearance of the 
nucleus ; very probably it is fecundated within the ovary ; it has only 
one cover when leaving the body of the mother, then one, two, four, and 
eight nuclei make their appearance within it before the outside division 
begins. At about the eighth division, the nutritive part of the vitellus, 
consisting chiefly of deutoplasm, begins to be enveloped by a continuous 
stratum of blastoderm secreting a chitinous layer, which may be considered 
as the first moulting. The egg increases in size during the development 
of the embryo in all Decapoda. The embryos of all genera observed by 
the author have the form which has been called “ porimorula ; ” this is 
changed by invagination in the midst of the germinal disk into a “ gas- 
trula,” but the anterior part of the head takes its origin independently 
of the germinal disk from a pair of protuberances, which are afterwards 
united. The mouth of the gastrula becomes the vent of the later animal, 
and the whole invagination the posterior part of the intestine ; whereas 
the later mouth and the anterior part of the intestine are formed very late, 
and do not at first communicate with the stomach. The mesoderm is 
derived from the ectoderm ; the endoderm is secreted by the cells in the 
bottom of the gastrula, and is formed later than the mesoderm. In the 
dorsal part of the embryo, parts of the yelk remain unchanged for rather 
a long time. Finally, the author calls attention to the number of 
bristles at the end of the tail in the Zoea-stage ; he states it to be nor- 
