NOV 27 1*^ 
JOUENAL 
OF THE 
ROYAL MICROSCOPICAL SOCIETY. 
OCTOBER 1894. 
SUMMARY OF CURRENT RESEARCHES 
Relating to Zoology and Botany ( principally Invertebrata and Crypto - 
gamia), Microscopy, &c., including Original Communications from 
Fellows and Others .* 
ZOOLOGY. 
A. VERTEBRATA : — Embryology, Histology, and General, 
a. Embryology. f 
Morphology of Placenta.* — Under the title of “ Spolia Nemoris,” 
Prof. A. A. W. Hubrecht gives a general and preliminary account of his 
observations on the placentae of Mammals collected during a trip to the 
Indian Archipelago. Of the Insectivore Tupaia javanica he was able 
to make a large collection ; Galeopithecus, Nycticebus , and Tarsius, with 
Manis, were all collected in great numbers. For some of these, as earlier 
for the European Sorex, he was able to establish without doubt that the 
number of fecundated eggs, and even of early blastocysts, is constantly 
found to be greater than the number of ripe foetus that form the normal 
contents of a litter. 
After a general account of the placenta in each of these five genera the 
author proceeds to discuss the origin and morphological significance of the 
cell-layers which constitute the two-layered blastocyst of Mammals, and 
the origin, minute anatomy and morphological significance of the pla- 
centa. Divergencies are so marked that, it is concluded, a larger 
number of genera must be investigated and compared before the time 
arrives for new theoretical generalizations. 
Maturation of the Ovum in Mammals.§ — Prof. M. Holl has studied 
this in the mouse, and in less detail, in the guinea-pig, rabbit, cat, cow, 
and man. He begins with a description of the young primitive ova. 
They lie at first among and afterwards under the superficial epithelial 
* 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 actualhj 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. t Quart. Journ. Micr. Sci., xxxvi. (1891) pp. 77-125 (4 pis.). 
§ SB. Akad. Wiss. Wien, cii. (1893) pp. 249-308 (3 pis.). 
1894 2 P 
