SUMMARY OF CUPiEENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(PEINCIPALLY INVERTEBRATA AND CRYPTOGAMIA), 



MICROSCOPY, Etc.* 



ZOOLOGY. 

 VERTEBRATA. 



a. Embryolog-y. t 



Influence of Foreign Sperm on the Ovum.J — ^E. Godlewski, jun. 

 has tried the effect of a considerable quantity of Chsetopterus sperm on 

 sea-urchin ova. In 2-5 minutes all the eggs form a " fertilization-mem- 

 brane." Segmentation follows, and in some species a blastula is reached. 

 But sooner or later a sort of cytolysis sets in, and in half-an-hour the 

 embryo may be quite disintegrated. If the development is to succeed 

 there must be a combination of the foreign sperm and the influence of 

 a hypertonic medium. If the sperm of Clisetopterus mixed with that of 

 sea-urchins be applied to the eggs there is no membrane formed in any 

 case. There must be an antagonistic influence between the two kinds 

 of sperm. The same happens when the sperm of Dentalium is mixed 

 with that of sea-urchins ; the latter is unable to eifect fertilization. It 

 appears that the eggs as well as the spermatozoa are prejudicially affected 

 by the mixture. 



Testis of Guinea-chicken Hybrids. §—M. F. Guyer finds that while 

 the testes of three guinea-chicken hybrids were of normal size (and 

 another was greatly hypertrophied) no spermatozoa were developed, and 

 the seminiferous tubules were few in number in most regions of the 

 testis and often contained disintegrating and defective cells. As in 

 hybrid pigeons the critical point seemed to be the synaptic phase, the 

 chromosomes of different parentage seemingly being unable to unite 

 normally in many instances. In spite of this difficulty, however, not a 



* 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 

 ptiblished, and to describe and illustrate Instruments, Apparatus, etc., 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, Reproduction, and 

 allied subjects. 



% Bull. Internat. Acad. Sci. Cracovie (1911) pp. 796-803. 



§ Journ. MorphoL, xxiii. (1912) x^p. 45-55 (2 pis.). 



