603 
SUMMARY 
OF CURRENT RESEARCHES RELATING TO 
ZOOLOGY AND BOTANY 
(principally Invertebrata and Cryptogamia ), 
MICROSCOPY, &c., 
INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS ANI) OTHERS* * * § 
ZOOLOGY. 
A. VERTEBRATA: — Embryology, Histology, and General. 
a. Embryology, f 
Vitelline Body of Balbiani in Egg of Vertebrates.:}: — M. L. F. 
Henneguy finds that the vitelline nucleus or so-called vitelline body of 
Balbiani is a constituent of the egg which may be observed in animals 
belonging to every class ; its existence in a given species is nearly 
constant. Although presenting numerous variations, it may be said to 
consist of a central body surrounded by a more or less modified zone of 
protoplasm, which gives it the appearance of a cellular element. It does 
not appear till the primordial ovum has ceased to multiply and begun to 
grow. It arises from the germinal vesicle, and appears to be formed by 
the nucleolar substance, which it resembles in its relations to staining 
fluids. It generally disappears very early in Vertebrates, while the egg 
is still but little developed, but in certain Invertebrates it may persist 
in the ripe egg, and be found even in the embryo. 
The author regards it as an ancestral organ which, with the nucleolar 
elements of the germinal vesicle, corresponds to the macronucleus 
of Infusoria ; the micronucleus is represented by the chromatic net- 
work, which alone takes part in the phenomena of fecundation. 
Centrosome and Yolk-nucleus. § — Though M. E. G. Balbiani has 
investigated these bodies in Spiders, where he finds the yolk-nucleus 
* The Society are not intended to be denoted by the editorial “ we,” and they do 
not hold themselves responsible for the views of the authors of the papers noted, 
nor for any claim to novelty or otherwise made by them. The object of this part of 
the Journal is to present a summary of the papers as actually published , and to 
describe and illustrate Instruments, Apparatus, &c., which are either new or have 
not been previously described in this country. 
t This section includes not only papers relating to Embryology properly so called, 
but also those dealing with Evolution, Development, and Reproduction, and allied 
subjects. 
X Journ. de l’Anat. et de la Physiol., xxix. (1893) pp. 1-39 (1 pi.). 
§ Tom cit., pp. 145-79 (2 pis.). 
