146 SUMMARY OF CUERENT RESEARCHES RELATING TO 



old ditches, and particularly water where masses of Charace^B grow. 

 The principal time of vegetation is in late autumn and before spring 

 begins ; in other words, at the period when the great decay of vegetation 

 takes place. Either fresh- or sea-water, and especially sulphur springs, 

 are favourable for the production of sapropelic organisms. Apart 

 from the bacteria and animal oi'ganisms recorded, the author mentions 

 as characteric certain species of Oscillatoria and Lyngiya, Splndina 

 Jiavovirens Wisl. and Pseudanahsena consfricfa Lauterb. and P. catenata. 

 Diatoms and Chlorophycefe are to a certain extent negatively character- 

 istic. A notable point are the pseudovacuoles of many sapropelic 

 Cyanophyceae, called by Molisch airosomes. They probably contain, 

 stored up, a product of metabolism, which is physically very labile, and 

 can be drawn on as a source of energy. The principal part of this 

 paper is zoological. 



Algae of North Croatia.* — J. Pevalek pubhshes the results of his 

 three-years' exploration of North Croatia for algre. He records 200 

 species, of which two are new. The ecology is fully discussed. The 

 most interesting point of the paper relates to the periodicity of the 

 species of Spirogyra. In the early spring only quite thin species with a 

 single chlorophyll band occur, S. Weberi, S. varians, 8. porticaUs. In 

 summer thicker species occur, which are more intensely coloured, with 

 several chlorophyll bands, and with not folded partition walls. In 

 autumn the species are once more thin and pale. The author attributes 

 this periodicity to the change in the light intensity, comparing the 

 chlorophyll bands to the palisade cells of leaves. Further, the author 

 confirms Molisch's observation on the phycoerythrin of Porphyridkwi 

 cruentmn. Notommata galls on Vaucheria were studied, and the active 

 penetration of the parasite into the algal filaments was observed. 



Algae of Wisconsin Lakes-j — Gr. M. Smith describes new species 

 of alg^e collected from the lakes of Wisconsin, and adds notes on other 

 species. Camera lucida drawings illustrating the structure of all the 

 plants are given. Eleven new species and four varieties are defined, 

 also a new genus, Glceocystopsis, which combines the general morphological 

 characteristics of C'/wofys^/s Naeg. and the cell shni^e of JVephrocytium 

 Naeg. The mucilaginous cell-wall is not laminated ; the cell is curved 

 sausage-shaped, not ovoid. The reproduction requires further study. 



Codium mucronatum.J — Annie M. Hurd has made a study of 

 Codium nnaronatum l)ased on material from Puget Sound. Her object 

 is to determine the validity of the varieties californicum and tiovse-zelandise 

 J. Ag., and to establish specific characters sufficient to distinguish the 

 species. She draws up a detailed diagnosis and decides that the 

 varieties based on variation in the mucronate tip are not justified, since 

 all variations are often found on the same plant. 



* Bull. Trav. Ac. Sc. Slaves du Sud Zagreb. CI. Sc. Math.-Nat., Sv. v. (1916) 

 pp. 121-32. See also Bot. Centralbl., cxxxii. (1916) pp. 433-4. 



t Bull. TorreyBot. Club, xliii. (1916) pp. 471-83 (3 pis.). 



% Puget Sound Marine Stat., Publ. i. (1916; pp. 109-35 (6 pis.). See also Bot. 

 Gaz., Ixii. (1916) p. 336. 



