ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 387 



Vegetable Protistology.* — J. Pavillard gives a careful review of the 

 discoveries made in the field of protistology, and discusses work done on 

 Cyanophycese, Phyloinonadinse, Dinoflagellata, and Bacillariales, by 

 numerous authors. 



Black Sea Algge.f — A. Henckel briefly describes the anatomical 

 structure of Gystoseira barbata, which undergoes considerable modifica- 

 tion when growing in the concentrated waters of the Gulf of Karkenit, 

 in the Black Sea. It loses its rigidity, becomes more cartilaginous, 

 the intercellular spaces become larger, and the parenchyma more lax. 

 On the other hand, the cavity (Hohlraum) is less differentiated. The 

 colour of such plants is light yellow to light brown ; and they might 

 easily be mistaken for a totally different species, were it not for the 

 complete series of intermediate forms. The author finds between the 

 typical assimilating tissue and the inner mechanical tissue a transitional 

 layer like that which is demonstrated in Ghordaria ft a. /r 1 1 if or mis, having 

 the same characteristic pores and many Fucosan-grains. These latter 

 stain deep black with osmic acid, and are usually congregated round the 

 nucleus. These fat-bodies have clearly been misunderstood by some 

 authors. Another peculiarity of the strongly saline waters of the Gulf 

 of Karkenit is the abundance of Chara tomentosa. 



Stichococcus bacillaris.J — S. M. Wislouch describes his experi- 

 ments in the cultivation of 8. bacillaris under different conditions. He 

 submitted plants grown on four different nutritive media to the action 

 of intense cold, the temperature in one experiment sinking to - 75°C. 

 The following conclusions were arrived at : 1. The resisting power of 

 S. bacillaris towards cold depends on the age of the culture, very young 

 cultures, 5-8 days old, showed much less resistance than those which 

 were 34-148 days old. The reason for this is said to arise from the 

 number of cells which are in the act of dividing or are still young, and 

 are therefore very sensitive to cold. 2. Winter cultures, which had 

 been raised during the dark months, showed far more power of resistance 

 than spring cultures, which had been grown in the lighter months, since 

 in the latter the number of dividing and of young cells was larger, and 

 the cultures were therefore more sensitive. 3. On the assumption that 

 cells grown on the usual Beijerinck's agar may be regarded as normal, 

 the author comes to the conclusion that the further a cell diverges from 

 the normal type the more easily is it destroyed by cold. 4. Cells of the 

 same age and belonging to the same culture are not equally resistant to 

 cold : a few cells can resist a temperature of - 75° C, while about 50 p.c. 

 of the cells are destroyed by a temperature of - 24° C. 



Effect of Coloured Light on Stichococcus bacillaris.§ — G. A. 

 Nadson cultivated this alga in H p.c. agar in Beijerinck's nutritive 

 solution, in a red-yellow light passing through a solution of potassium 

 bichromate, and in a blue light passing through cupric-ammonium 



* Progressus Rei Botanic?e, iii. (1910) pp. 474-544. 



t Forbandl. Nordisk. Naturf. och Lakarembt. Helsingfors (1903) Sect. vii. Bot., 

 pp. 6-7. j Bull. Jard. Imp. Bot. St. Petersbourg, x. (1910) pp. 166-80. 

 § Bull. Jard. Imp. Bot. St. Petersbourg, x. (1910) pp. 137-50. 



