ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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somewhat telolecithal. In the descriptive portion the author makes 
such repeated references to his illustrative figures as to render it impos- 
sible to give a clear account of his observations without reproducing 
them. We may note that he has observed a nauplius-stage, in which 
the appendages are tipped with spines. As in several higher Crustacea, 
though not in Astacus, there is an ocellus. The author’s descriptions 
cease at a stage which may be compared with the earliest figured by 
Mr. S. J. Smith. 
Formation of Germ-layers in Crangon vulgaris.* — Prof. W. F. It. 
Weldon gives a detailed account of the formation of the germ-layers in 
this Crustacean ; in many important ))oints bis results are quite at 
variance with those of J. S. Kingsley, though they are in accordance 
with the account given by Nusbaum of tho corresponding process in 
Mysis. A discussion of the results arrived at is postponed till the author 
has carried his researches further. 
Development of Diptychus.f — M. E. L. Bouvier has investigated 
the development of this Galatheid, and finds that it resembles in all 
essential points that of the Astacine Crustacea. The characteristic 
features in its development are the displacement of the arthrobranchs 
and the delay in the escape from the egg. Although this latter is not 
so great as has been supposed, the retardation is obviously favourable to 
the preservation and development of the species ; it compensates for the 
inferiority which is due to the small number of eggs, and recalls, to a 
certain point, the history of Hyla martinicensis where the tadpole-stage 
is passed within the egg. 
The Genus Glaucothoe.J — M. E. L. Bouvier raises the question 
whether the forms placed in the genus Glaucotlioe are not really 
Pagurine larvm. He finds that such examples as have been considered 
perfect by certain carciuologists have no sexual orifices or ophthalmic 
scales, and the absence of these are larval characteristics. They are 
certainly Pagurine, and have only distant relations to the Thalassinidae. 
They form a polymorphous group, and probably contain as many forms 
as there are genera of Paguridae. The species as yet known are more 
allied to the asymmetrical Pagurids than the primitive Pagurids. The 
rarity of Glaucothoids of large size may be explained by supposing that 
large specimens are larvte less fortunate than the rest, which continue 
to grow until they can find a suitable home. All the known forms of 
Glaucotlioe are swimming creatures, found on the surface of the sea. 
Early Stages in Development of Hedriopthalmous Crustacea.§ — 
M. L. Boule signalizes the diffused origin of the mesoderm of these 
Crustaceans, which arises from almost the whole of the blastoderm. 
Another important fact is the double origin of the endoderm, the two 
original bands of which are separated by a large space. The combination 
of these two characters is truly characteristic, for they are not met with 
in the condensed developments of other Coelomata. A phenomenon of 
great importance is exhibited by the archenteron, which is hollowed out 
* Quart, Journ. Micr. Sci., xxxiii. (1892) pp. 313-63 (3 pie.), 
t Coinptes Rendus, cxiv. (1892) pp. 767-70. 
j Ann. Sci. Nat., xii. (1891-2) pp. 65-82. 
§ Comptcs Rendus, cxiii. (1891) pp. 86S -70. 
