SUMMARY OF CURRENT RESEARCHES RELATING I" 



limited bo a semicircular equatorial groove. It is obvious that the new 

 type is of unusual interest. 



Protozoa. 



Studies on British Foraminifera.* - E. Heron-Allen and Arthur 

 Earland contribute interesting and beautifully illustrated studies of 

 \fassilina secans d'Orbigny and Polystomella crispa L.. the two com- 

 monesl Foraminifera in English shore-gatherings. 



Antarctic Rhizopods.f — Eugene Penard reports on tin- Sarcodina 

 • Mllected by James Murray in the ' Nimrod ' expedition. They were 

 obtained from among moss. There are no fewer than seventy-nine species. 

 mostly cosmopolitan, but some of considerable interest. 



Reactions of Amceba to Light.J — S. 0. Mast has made a study of 

 the reactions of Amoeba to light. He found that a sudden and sharp 

 increase of light causes retardation or cessation of movement in Amoeba 

 proteus. This effect may be local if the increase is local. If the intensity 

 is very gradually increased it produces no response, showing that the re- 

 action of Amoeba is dependent primarily on the change of intensity. 

 A. proteus is negative in strong light, and orients fairly accurately. 

 Orientation is brought about bv the inhibition of the formation of 



... 



pseudopods on the more highly illuminated side. This is probably due 

 to local changes of intensity, owing to the movement of the protoplasm 

 and the resulting shadows of one part passing over others. There is no 

 evidence that the direction of the rays, or the absolute intensify of light 

 ou the whole organism, has any effect apart from producing changes of 

 intensity. The blue (430-490 /u,/*) in the solar prismatic spectrum is 

 nearly as effective in causing reactions in A. proteus as white light. 

 Violet, green, yellow, and red are only very slightly active. The author 

 considers it highly probable that different photochemical changes are 

 associated with the reactions to light in different organisms. 



Experiments on Paramcecium.§— K. R. Lewin has been able to 

 divide living specimens of Paramoecium en mint inn. so that each fragment 

 has a piece of meganucleus, but only one has the micronucleus. The 

 " amicronucleate " forms were able to propagate by normal fission. 

 The animals seem quite normal, though the culture was not very vigorous. 

 A race was produced without visible micronuclei. It is possible that the 

 micronucleus exerts some influence on the rate of division. 



The experiments show, as regards P. caudatum, that Le Dantec's 

 statement as to the regeneration of the micronucleus from the mega- 

 nucleus after merotomy, is incorrect. They also demonstrate that the 

 interaction of cytoplasm and meganucleus is sufficient to maintain the 

 discontinuous growth of the cell during a considerable period. 



Effect of Inanition on Paramc3cium.|| — Irene Lipska has studied 

 the effects of inanition on Paramoeeium caudatum. The duration of 



* Knowledge, xxxiii. (1910) pp. 285-6 ; 304-6 (3 figs.) ; 376-9 (7 figs.). 



t Rep. Sci. Invest. Brit. Antarc. Exped.. 1907-9, i. (1911) pp. 203-62 (2 pis.). 



X -Journ. Exper. Zool. ix. (1910) pp. 265-77 (2 figs.). 



§ Proc. Cambridge Phil. Soc, xvi. (1911) pp. 31-41 (1 fig.). 



11 Rev. Suisse Zool., xviii. (1910) pp. 591-643. 



