ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
33 
vitelline body. The second chapter deals with its disintegration, and 
the associated changes in the nucleus and vitellus. Thirdly, the author 
describes the fatty degeneration of the elements which arise from the 
disintegration of the vitelline body. The fourth chapter is devoted to a 
description of the progressive vacuolisation of the vitellus, consequent 
on the appearance of vitelline spheres. Associated therewith is the 
establishment of a closer relation between vitellus and nucleus, and an 
increase in the surface of contact. Finally, the author examines all the 
views propounded as to the role of the vitelline body, and concludes that 
it is the centre of formation for the nutritive elements of the vitellus. 
e. Crustacea. 
Dorsal Organs of Crustacean Embryos.* — Prof. J. Nusbaum and 
Herr W. Schreiber have studied these structures (“ Buchenorgane ”) in 
Mysis Lamournse, Idotea tricuspid ata, and Cymothoa cestroides, and cor- 
roborate Wagner and Rossijskaja-Koschewnikowa as to the simultaneous 
occurrence of both dorsal and dorso-lateral organs, though they do not 
regard them as morphologically distinct. Both of these, and the incon- 
stant accessory dorsal organs as well, are coenogenetic structures which 
contribute to the reduction of the vitellocyte layer. 
Vitality of Entomostraca.t — Mr. E. Atkinson relates that in 1858 
he took some dried mud silvered over with minute shells of Entomos- 
traca from the pool of Upper Gihon at Jerusalem. The pool contains 
water only during the two months of the rainy season, and Mr. Atkinson 
inferred that the ova of the crustaceans must live through the other ten 
months in the sun-baked mud. To test this, a quantity of the dry mud 
was sent home to England and moistened, and Ur. Baird, who examined 
the water, found in it six new species of living Entomostraca. During 
summer the water was entirely drawn oif by means of a siphon, and the 
mud left undisturbed till the following spring, when fresh water was 
again added to it, with the same result as before. The experiment was 
repeated year after year by several observers, always with a like result. 
In one case, a portion of mud was moistened regularly until 1884, then 
left dry till 1894, when a fresh supply of water restored the annual 
activity, which is still maintained. 
Entomostraca of Lake Bassenthwaite.j; — Miss E. M. Pratt gives an 
account of these as found at different seasons of the year. In an intro- 
ductory note, Prof. S. J. Hickson reminds us how ignorant we are of 
the fauna of our own English lakes, and indicates that it might be practi- 
cally worth while to study the relations between the fish-fauna and the 
Entomostracan fauna. 
Entomostraca of Epping Eorest.§ — Mr. D. J. Scourfield has brought 
together the result of eight years’ observations on the Entomostraca of 
the Epping Forest area. It appears that no less than 103 species have 
been seen in the district, comprising Cladocera 47, Branchiura 1, Ostra- 
coda 23, and Copepoda 32. Three of these and one variety are con- 
sidered to be new to the British fauna. As regards the periodicity of 
* Biol. Centralbl., xviii. (1898) pp. 736-46 (4 figs.). 
f Ann. Nat. Hist., ii. (1898) pp. 372-6. 
X Tom. cit., pp. 467-76. 
§ Essex Naturalist, x. (1898) pp. 193-210, 259-74, 318-34. 
1899 
D 
