SUMMARY OF CURRENT RESEARCHES. 161 



•compacta basalis, no decidua reflexa being present. The " wall " or cir- 

 cumvallation described by Selenka in Semnopithecidse is not present. 

 The uterine tissues immediately beneath the area of attachment of the 

 blastocyst, and also for some distance on either side of this, are oedema- 

 tous. Immediately beneath the blastocyst there is even an accumulation 

 of a fibrinous exudation, by which the apparently degenerating cells of 

 the uterine epithelium are thrust off. There is no evidence of the 

 transformation of cells either of the uterine epithelium or of the glan- 

 dular lining into syncytial masses. The evidence of the sections leads 

 to the conclusion that the intervillous spaces are not lined by any deri- 

 vatives of maternal cells, but by embryonic ectodermal cells. The 

 epithelial lining cells of the uterine glands seem to play no permanent 

 part in the formation of placental tissues. The embryonic tissue which 

 has permanent relations in the placenta as ultimately constituted is 

 identified with Voigt's Grundschicht of the villous processes (Pcytotro- 

 phoblast of other authors). In the stage described there was no meso- 

 derm in the embryonic villi. 



Formation of Red Blood Corpuscles in Placenta of G-aleopithecus.* 

 A. A. W. Hubrecht finds clear evidence of haematopoiesis, not only in 

 the maternal mucosa, but also in the embryonic trophoblast. He finds 

 that the blood corpuscles thus formed circulate in the maternal blood- 

 vessels only. Incidentally he adds evidence in favour of the view that 

 the red blood corpuscles in mammals are not equivalent with cells, but 

 must be regarded as nuclear derivatives. 



j &"- 



Growth of Testes in Birds and Mammals.f — R. Disselhorst calls 

 attention to various facts which show that the growth of the testes in 

 birds and mammals is for a long time relatively independent of that of 

 the body generally. While other organs are showing their maximum 

 rate of growth, the testes remain in a latent state. This condition is 

 paralleled by that of the testes in hibernating animals, and in birds out- 

 side of the breeding season. The author refers to a paper which he 

 published in 189s, J in which he discussed the changes of weight in the 

 gonads at different periods of life. 



Incubation in Doves.§ — Xavier Raspail notes that a turtle-dove 

 (Turtur auritus) twice in succession left its eggs on the eighteenth day, 

 the eggs not developing. A carrier pigeon did the same four times on 

 the eighteenth day, the eggs not developing. He concludes that the 

 birds become aware of the futility of brooding any longer. The turtle- 

 dove is very sensitive, knowing when " a profane hand " has, in its 

 absence, touched the eggs or the young, and leaving them in conse- 

 quence ; it is surprising that it does not become sooner aware that the 

 eggs are not developing. 



Amitosis in Pig-eon's Egg.|| — J. T. Patterson finds that amito.sis 

 plays an important role in the development of the pigeon's blastoderm. 



* Proc. Acad. Amsterdam, Section of Sciences, ix. (1907) pp. 873-8. 



t Anat. Anzeig., xxxii. (1908) pp. 113-17. 



J Arch. wiss. Tierheilkunde, xxiv. (1898) heft 6. 



§ Bull. Soc. Zool. France, xxxii. (1907) pp. 89-90. 



|| Anat. Anzeig., xxxii. (1908). pp. 117-25 (24 figs.). 



