& 



ZOOLOGY AND BOTANY. MICROSCOPY, ETC. 487 



and to the substrata to which they adhere ; marine, lacustrine and pond 

 floras; the flora of running water ; plankton; aerial alga) ; collection of 

 alga? and phy to-biological exploration of the various aquatic media ; 

 preparation and preservation of algas. 



Japanese Algae.* — K. Okamura publishes the tenth part of his 

 Icones of Japanese Algse, containing detailed figures of the following 

 species : — Gelidium subcostatum Okam., Ptilota pectinata (Gunn.) Kjellm., 

 P. asplenioides (Turn.) Ag., P. califomica Rupr., Cdlosipkonia vermicu- 

 lar is (J. Ag.) Schm., Ceramium Boydenii Gepp. The text is in Japanese 

 and English. The title-pages and index completing the first volume are 

 included. 



Physiology of Desmidiacete.f — A. Andreesen describes his experi- 

 ments in cultivating singly the commonest forms of desmids, with a view 

 to testing their behaviour in certain nutritive solutions, and to bring- 

 about cell-division. The various organic and inorganic compounds em- 

 ployed are described, and interesting results were obtained. The author 

 summarises his results as follows : — 1. Division of Desmidiaceas is 

 specially induced by amide compounds of nitrogen. 2. Normal con- 

 ditions of air-pressure and light are indispensable for division, even with 

 organic nutrition. 3; Certain forms, such as Closterium moniliferum, 

 show themselves to be entirely adapted to organic nutrition. 4. A 

 generation in the Desmidiaceas lasts 48 hours under favourable con- 

 ditions. 5. Plasmolysed cells form no membrane ; after recovery from 

 plasmolysis the cells may form another membrane-cylinder in the ring- 

 furrow. 6. After plasmolysis, the plasma loses permanently or 

 temporarily the power of division, but recovers it under favourable 

 conditions. 7. In unfavourable conditions the transverse wall fails to 

 form in the division of Closteriua/, and hence arise abnormal cells. 

 8. In strongly osmotic solutions to which have been added substances 

 which induce division, checked growths (Hemmungsbildungen) arise, 

 and these are capable of further division. Simdar results are obtained 

 by culture in low temperatures. 9. Prolonged cultivation in organic 

 nutritive solutions produces a granular precipitate in the cytoplasm of 

 Closterium and Gosmarium. 10. Organic nutrition apparently cannot 

 in the Desmidiaceae take the place of the assimilation of carbon. 11. In 

 unfavourable conditions the chloroplasts of Closterium show remarkable 

 signs of degeneration, such as shrivelling and crumbling ; the latter 

 occurs at a special point, viz., at a third of the half -cell from the middle. 

 Cells with shrivelled chloroplasts are still capable of division. 



Two New Species of Characium.l — F. D. Lambert describes two 

 new species of Characium, C. gracilipes and C. cylindricum, which he 

 found in Massachusetts growing on Branchipus vernalis in a small 

 pool. C. gracilipes occurred in greatest abundance on the flat surfaces 

 of the two sides of the abdominal appendages of Branchipus, and rarely 

 on the marginal hairs for which C. cylindricum seems to show preference. 

 In respect to size, both species differ greatly from all others hitherto 



* Tokyo : 1909, i. No. 10, pp. 233-58 (5 pis.). 

 t Flora, xcix. (1909) pp. 371-413 (figs.). 

 % Kbodora, xi. (1909) pp. 65-74 (pi.). 



