SUMMARY OF CURRENT RESEARCHES 



EELATING TO 



ZOOLOGY AND BOTANY 



(PEINCIPALLY INVEETEBEATA AND CEYPTOGAMIA), 



MICRO SNOOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 



a. Emtoryolog-y.t 



Antagonism of Spermatozoa of Different Animals.^ — M. Herlant 

 put the eggs of a sea-urchin {Strongylocentrotus) into sea-water with 

 mixed spermatozoa, e.g. of sea-urchin and limpet, or sea-urchin and 

 mussel, or sea-urchin and Ascidian. He observed what Godlewski has 

 called the " antagonism " of the spermatozoa of unrelated species. The 

 spermatozoa do not show any appreciable change in structure or move- 

 ment in the mixture. But the mixture brings about a change in the 

 physical state of the surface of the ova ; the spermatozoa are unable to 

 penetrate ; fertilization is inhibited. 



Yolk-nucleus. § — J. P. Munson has studied the yolk-nucleus in 

 spider, king-crab, crayfish, frog, pigeon, cat, etc. The term has been 

 applied to real nuclei, to karyolymph, to metaplasm, and to the centro- 

 sphere. 



Real nuclei in the cytoplasm of the ovum may be due to phagocytes 

 or to a degenerative fragmentation of the germinal vesicle. The karyo- 

 lymph produced by the chromatin may pass out from the nucleus and 

 set up changes in the cytoplasm, resulting in metaplasm. 



The true yolk-nucleus is a centrosphere. It is typically an aster 

 with a centrosome and concentric circles. The growth of the cytoplasm 

 of eggs is largely due to the actual growth of this body. The relation 

 of the yolk-nucleus or vitelline body to the germinal vesicle is such as 

 exists between the centrosome and chromosomes after karyokinesis. Its 

 connexion is such that it serves as a reservoir, into which the karyo- 



* 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 pub- 

 lished, 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. 



X Anat. Anzeig., xlii. (1912) pp. 563-75 (1 fig.). 



§ Arch. Zellforsch., viii. (1912) pp. 663-716 (6 pis.). 



