ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
677 
legs; these remnants fuse together, and form the coxal gland. In the 
abdomen, also, all the coelomic cavities disappear except the unpaired 
one in the caudal lobe, which remains as the stercoral pocket. 
Development of Scorpion.* — Dr. A. Brauer has studied the develop- 
ment of Eiiscorpius carpathicus L. (younger stages) and E. italicus (older 
stages). The result of segmentation is a single-layered, circular or oval 
plate, with a more or less watchglass-like curve. The cells of this 
blastoderm are very small, and lie on the yolk at the pole towards the 
oviduct. They show considerable irregularity in arrangement. 
An excentric white spot appears on the embryonic disc and gradually 
spreads over it ; the blastoderm cells are dividing radially, and those 
next the yolk are Rliizopod-like with large nuclei and vacuoles. Most 
of these are yolk-cells, which, as others have shown, take no direct part 
in forming the embryo. But the thickened white spot also includes a 
group of cells which turn out to be genital cells and define the posterior 
end of the embryo. The first spindle-shaped endoderm cells are also 
detected between the yolk cells on the one hand, and the ectoderm or 
the genital rudiment on the other. There is ample reason to deny that 
the yolk cells share in the formation of this endoderm, and the reverse 
process is highly improbable. From proliferation of the ectoderm, 
especially in front and at the sides of the thickened region, the mesoderm 
arises. It will be noted that in the interpretation of the thickened area 
as the genital rudiment, and not as the rudiment of the ento-mesoderm, 
&c., Brauer differs from Kowalevsky, Schulgin, Metschnikoff, and Laurie. 
In regard to the formation of the embryonic envelopes, his results are 
in agreement with those of Laurie. 
Parthenogenesis in Plumieolous Sarcoptidse.f — M. E. Trouessart 
finds that Syringobia chelopus, a parasite in the feathers of Totanus calidris ,. 
has two female forms, one of which is sexual, while the other developes 
parthenogenetically. In the absence of males the developing female 
does not pass to the second nymph-stage, but grows to twice its usual 
size, and then changes after one eedysis into a female which developes 
parthenogenetically. It lays soft eggs, whence emerge a series of larvas 
and nymphs, different from those that are produced sexually, and ending 
in parthenogenetic females. Very rarely, and in the ratio of about 1 to 
300, an extraordinary male appears, but this is sterile, for the female of 
this series has no copulatory orifice. 
€. Crustacea. 
European and Chilian Crustacea.^— Dr. R. A. Philippi has noted 
some resemblances between the Crustacean fauna of Europe and Chili, 
which are, he thinks, something more than chance likenesses. To them, 
he says, are confined the genera Lithodes , Atelecyclus, and Pirimela. 
He finds an explanation in the hypothesis that similar, and perhaps even 
identical creatures, are found wherever similar conditions of life obtain. 
Reproduction of Lobster.§ — Mr. F. H. Herrick finds that many of 
the statements regarding the breeding habits of Homarus americanus are 
conflicting. With regard to the date of oviposition, most lobsters ex- 
* Zeitschr. f. wiss. Zool., lvii. (1894) pp. 402-32 (2 pis., 6 figs.). 
t Bull. Soc. Entom. France, 1894, pp. cxvii.-xx. See Zool. Centralbl., i. (1894) 
pp. 639 and 40. 
X Zool. Anzeig., xvii. (1894) pp. 264 and 5. § Tom. cit., pp. 289-92. 
1894 3 A 
