ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
435 
germinal layers is a misunderstanding. The primitive form of every 
embryo (except in Arthropods) is a blastula, typically ciliated and 
bipolar ; the more active anterior cells become freed from alimentary 
reserves (which accumulate posteriorly), and multiply quickly ; there 
are two alternatives : — that the blastula remains free or becomes fixed : 
if it remains free the posterior region is necessarily invaginated by the 
more rapid growth of the locomotor anterior region ; if it becomes fixed 
(as in Sponges) the ciliated region is covered by the granular region. 
But this is not reversal of layers. 
Prof. Y. Delage * * * § answers Prof. E. Perrier’s criticisms, but main- 
tains that there are only two alternatives. Either the direction of 
invagination is normal, and the endoderm is disguised as ectoderm, and 
reciprocally ; or the layers retain the histological characters which they 
have elsewhere, and the direction of invagination has been reversed. 
Germinal Layers in Oscarella.f — Dr. O. Maas describes the early 
development of Oscarella and Halisarca, and concludes that this is no 
special type, but that it shows a diploblastic larval stage, with granular 
cells posteriorly, and flagellate cells anteriorly, — layers which corre- 
spond to those in Sycandra , Ascones , siliceous, and horny sponges. The 
author then proceeds to discuss the possible interpretations : — (a) if 
we compare the sponge-layers with those in other Metazoa, and ( b ) 
if we do not. He refrains from any dogmatic conclusion ; but his 
arguments must be considered along with those of Delage and Perrier 
noticed above. 
Protozoa. 
Protozoa of the Balaton Lake.J — Herr E. France enumerates 191 
Protozoa from the “ Balatonsee ” ; 24 Ehizopods, 13 Heliozoa, 90 Masti- 
gophora, and 64 Infusoria, including several new forms. He thinks that 
the distribution is affected not so much by climatic and meteorological 
conditions as by the state of the water and the associated plants. 
Modifications in Protozoa.§ — J. Kiinstler discusses the modifica- 
tions resulting from change of environment, e.g. in a new habitat, but 
his remarks are confined to generalities. 
New Genus of Eoraminifera,|| — Mr. F. Chapman describes Had- 
donia g. n. collected by Prof. A. C. Haddon in the Torres Straits. The 
salient characters of the genus are stated in the following terms : — Test 
calcareo-arenaceous, adherent, and sinuous ; the commencement some- 
times straight, sometimes spiral. Chambers imperfectly septate or 
openly labyrinthic. Shell-wall coarsely porous. Thirty-one distinct 
specimens were attached to a piece of rock measuring about 5 by 4 in. 
The specific name given is H. torresiensis, and the genus is referred to 
the labyrinthic group of the sub-family Lituolinse. 
* Comptes Rendus, cxxvi. (1898) pp. 767-9. 
t Zeitschr. f. wiss. Zool., lxiii. (1898) pp. 665-79 (1 pi.). 
X Resultate d. wiss. Erforschung d. Balatonsees. Bd. ii. Tlieil i. Die Fauna 
des Balatonsees. 1897, pp. 1-64 (figs.). See Zool. Centralbl., v. (1898) pp. 322-3. 
§ Comptes Rendus, cxxvi. (1898) pp. 765-7. 
|| Journ. Linn. Soc. (Zool.), xxvi. (1898) pp. 452-6 (1 pi. and 1 fig.). 
