ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 257 



Ovarian Grafts in Goats and Sheep. — ED.RETTERERand S. Voron- 

 OFF (Comptes Reiulus Soc. Biol., 1921, 84, 104-6). In a goat ovarito- 

 mized on each side, one of the ovaries was embedded in the right cornu 

 and the other in the left cornu ; in another similar case a half of the ovary 

 of another goat was inserted in the right cornu, and half of one of its 

 own ovaries on the external surface of the uterus at the point of bifur- 

 cation. The grafts were wholly absorbed, but the presence of the 

 ovary in the cornu was followed by the development of a maternal 

 placenta. It looks as if the corpus luteum substance influences the 

 placental development of the uterine mucosa, but the peri-follicular 

 elements (interstitial cells, etc.) may also have their role in the produc- 

 tion of internal secretions. This is consistent with what happened in 

 the authors' experiments, where there was an absorption of all the 

 elements of the implanted ovary. J. A. T. 



Placenta of Goat. — Ed. Retterer and S. Yoronoff {Comptes 

 Rendus Soc. Biol., 1921, 84, 296-8). The elements of the maternal 

 part of the placenta, due to the hyperplasia and hypertrophy of the 

 epithelial cells, constitute a complex into which the chorionic villosities 

 penetrate and which is absorbed in contact with them. J. A. T. 



Ovotestis in Hermaphrodite Mammals. — E. Bujard {Comptes 

 Rendus Soc. i)W?., 1921, 84, 112-4, 114-6). According to the author the 

 mammalian ovary is a gonad with protandrous hermaphroditism more 

 or less latent. The male elements (medullary strands) may atrophy 

 completely as in the cat, or remain rudimentary ^as in mole and bitch, 

 or become foetal seminiferous tubules as in pig and man, leading 

 abnormally to an ovotestis. The teratogenic period is that of the 

 formation of the primitive cortical strands, which normally leads to a 

 thoroughly female gonad. The cause of a protandrous differentiation 

 of the medullary strands, leading to an ovotestis, remains obscure. 



J. A. T. 



Stages in Conjugation. — Jean Massart {Bidl. Glasse Sciences 

 Acad. Roy. Belgique, 1921, 7, 38-58). There are four stages : — (1) the 

 approximation of cells, (2) the union of cytoplasms, (8) the union of 

 nuclei, and (4) the union of chromosomes. In Coleochsete and other 

 green algge the four stages follow in close succession, without any 

 karyokinetic division between. In Metaphytes there is a long interval 

 between (3) and (4) ; the fused nuclei undergo numerous karyokineses 

 l:)efore their chromosomes are coupled. In Basidiomycetes it is the 

 interval between (2) and (3) that is inlportant. In a cell with fused 

 cytoplasm the nuclei remain distinct, and this dualism persists for a 

 long series of divisions. In Infusorians, Schizogregarines, Heliozoa and 

 Diatoms there is a long interval between (3) and (4), but the characteristic 

 feature is that the fourth phase does not occur unless it is prepared for 

 by phase 1. A preliminary cohabitation is necessary if the gametes are 

 to appear. In the Eugregarines there is furthermore a long interval 

 between (1) and (2) ; they are paired early, but the cytoplasm do not 

 unite till long afterwards. In many female animals a preparatory 

 cohabitation is necessary for the formation of gametes. J. A. T. 



