SUMMARY OF CURRENT RESEARCHES 



RELATING TO 



ZOOLOGY AND BOTANY 



(principally invertebrata and cryptogamia), 



MICROSCOPY, Etc.* 



ZOOLOGY. 



VERTEBRATA. 

 a. Embryolog-y.f 



Can Extract of Sperm act as a Fertilising Agent Pj — Dr. Hans 

 Winkler put the sperm-material of Sphserechtnus granularis or of Arbacia 

 pustulosa into distilled water, left it with repeated shakings for half an 

 hour, filtered five or six times through three folds of filter-paper, ad- 

 justed the salinity to that of normal sea-water, and added unfertilised 

 eggs of the same species. In some cases a small number of the ova 

 showed signs of segmentation (apparently with mitoses), regularly for 

 one or two cleavages, and then irregularly. In another experiment he 

 placed the sperm-material in water with about 20 p.c. of salt (to kill 

 them), and with this method he had similar results. What the nature 

 of the stuff is that passes through the filter remains quite obscure, nor 

 does the author regard his work as more than tentative. He reviews 

 some analogous experiments by others. 



Does Nutrition influence the Determination of Sex?§ — Dr. J. 

 F. Gemmill has extended and confirmed some previous observations || 

 bearing on this problem. If it be granted that high-level limpets and 

 mussels are relatively starved when compared with low-level forms, 

 it might be expected that this would be seen in some disproportion 

 between the sexes. But the author's results show that there is not a 

 greater relative proportion of males in the upper zones or of females in 

 the lower zones. 



Reaction of Developing Sea-Urchins to Environment. IF — Dr. H. 

 M. Vernon kept the impregnated ova of Strongylocentrotus lividus for 



* The Society are not intended to be denoted by the editorial " we," and they do 

 cot 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. 



t This section includes not only papers relating to Embryology properly so called, 

 but also those dealing witli Evolution, Development, Reproduction, and allied subjects. 



X Nachricht. Ges. Gottingen, 1900, Heft 2, pp. 187-93. • 



§ Commuuications Millport Station, i. (190U) pp. 32-6. 



| Cf. this Journal, 1897, p. 27. 



i Proc. Roy. Soc., lsvii. (1900) pp. 85-101. 



