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SUMMARY 
OF CURRENT RESEARCHES RELATING TO 
ZOOLOGY AND BOTANY 
( principally Invertebrata and Cryptogamia ), 
MICROSCOPY, &o., 
INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.* 
ZOOLOGY. 
A. VERTEBRATA : — Embryology, Histology, and General, 
a. Embryology. f 
Preservation and Accumulation of Cross-Infertility.:]: — The Rev. 
J. T. Gulick regards physiological segregation as including all kinds of 
incompatibility between the male and female elements of different 
groups, however closely or however widely they may be separated ; he 
urges that the importance of this principle in the origin and continuance 
of different groups cannot be exaggerated in the case of organisms whose 
fertilizing elements are fully distributed by wind or water; in those 
cases the segregate compatibility and cross incompatibility of the male 
and female elements may be the means by which the prevention of free 
crossing is secured, as well as the means by which the swamping effect 
of the crossing that occurs is prevented. 
Experimental Studies on Ova.§ — Prof. 0. Hertwig discusses under 
this title a number of strange facts. 
(1) The effect of over-ripeness. — At Trieste, in April 1887, the 
majority of the sea-urchins ( Echinus microtuberculatus and Strongylo- 
centrotus lividus) seem to have been in a pathological condition. The 
reproductive organs were over-ripe ; the ova would not fertilize at all, 
or were more frequently susceptible to multiple fertilization, containing 
sometimes a score of sperm-nuclei ; segmentation, if it did begin, 
was very abnormal. As Professor Hertwig does not believe in the pos- 
sibility of unfavourable external conditions having a direct effect on the 
reproductive elements, he inclines to think that spawning had been 
* 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. 
f This section includes not only papers relating to Embryology properly so called, 
but also those dealing with Evolution, Development, and Reproduction, and allied 
subjects. % Amer. Journal of Science, cxl. (1890) pp. 437-42. 
§ Jenaische Zeitschr. f. Naturwiss., xxiv. (1890) pp. 268-313 (3 pis.). 
c 2 
% 
