( 169 ) 
SUMMARY 
OF CURRENT RESEARCHES RELATING TO 
ZOOLOGY AND BOTANY 
(principally Invertebrata and Cryptogamia ), 
MICROSCOPY, &c., 
INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.* * * § 
ZOOLOGY. 
A. VERTEBRATA Embryology, Histology, and General. 
a. Embryology. f 
Fate of the Human Decidua reflexa.J — Prof. C. S. Minot has 
arrived at some conclusions in regard to the well-known but imper- 
fectly understood disappearance of the decidua reflexa. The view most 
generally accepted has been that it fused about the fifth month with 
the decidua vera, and that accordingly the layer of decidua nearest the 
chorion during the latter half of pregnancy represents the decidua reflexa. 
Minot has studied normal uteri of two, three, five to six, and seven 
months’ gestation. These show that at two months the decidua reflexa 
is undergoing hyaline degeneration, that at three months the degenera- 
tion is considerably more advanced, and that by the sixth and seventh 
months the reflexa can no longer be found. Therefore the theory seems 
justified that the reflexa degenerates and is completely absorbed. This 
is the more probable, since recent investigations have shown that in 
many placental mammals there is an extensive pseudo-pathological 
destruction of the mucosa uteri during gestation. As to the cause of 
the degeneration, Prof. Minot simply regards it as the result of a reflex 
nervous activity, 
Transplantation and Growth of Mammalian Ova within a Uterine 
Foster-mother.§ — Mr. W. Heape records an experiment by which it is 
shown that it is possible to make use of the uterus of one variety of 
rabbit as a medium for the growth and complete development of fer- 
tilized ova of another variety of rabbit. Two ova were taken from an 
* 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. t Anat. Anzeig., v. (1890) pp. G39-43 (1 fig.). 
§ Proc. Roy. Soc. Lond., xlviii. (1891) pp. 437-8. 
