ZOOLOGY AND BOTANY, .MICEOSCOPY, ETC. 71 



any paper hitherto published. After au introduction giving a short 

 resume of past work, the author deals with " The influence of external 

 factors," such as the geological character and configuration of the coast ; 

 the bottom, the salinity, and temperature of the sea ; and the influence 

 of the ice. Tables help to show these results. A section on " The 

 I'egional distribution of the marine flora " divides the area into the 

 three Kjellman regions — the littoral, the sublittoral, and the elittoral. 

 The species occurring in each of these are discussed, and an explana- 

 tion is given of the presence of certain algge brought up by the dredge 

 from considerable depths. They are brought by the icefloes which 

 run against the coast, and become packed and screwed together in 

 many ways. Algge attach themselves to the lower parts of these floes, 

 and, when the pack ice disperses, the waves wash the floes, and the 

 algae become detached and sink to the bottom. It is, of course, im- 

 possible to say how far this factor influences the distribution of the 

 species, but it is at least probable that it plays some part. A few 

 remarks are made on the characteristic formations. Then follow a list 

 of the dredging stations and a list of Antarctic alga3, not including the 

 undetermined part of the author's own collection, nor the collection of 

 the ' Discovery,' with a few general remarks. Photographs are given of 

 Desmarestia Harveyana, D. anceps, and Gracilaria sinipUx ; as well as a 

 map of Graham Land. 



Periodicity of Algae in Toulouse.* — J. Comere has made observa- 

 tions on the periodicity of development of the algae in the Toulouse region. 

 He comes to the following conclusions. The general distribution of 

 fresh-water algae is determined by the mechanical action of the various 

 temporary and permanent media, while the periodicity of development 

 is governed by the thermic influence of the various seasons of the 

 year. Running water is unfavourable to the growth of green algse, 

 owing to mechanical action and the poverty of the water in saline 

 substances ; more quiet streams of which the water is often disturbed 

 is no less unfavourable. Stagnant water shows an infinitely richer algal 

 flora. Under mixed conditions, where the water is constantly renewed, 

 he finds potamophilous diatoms, together with limnophilous Chlorophyceae 

 and Protococcoideae, having a periodicity of evolution similar to that 

 of the same species living in rapid and in stagnant water. The algae 

 produce a relatively large number of spores, etc., immediately before 

 threatened evaporation. 



Tropical Fresh-water Algae.j — E. Lemmermann describes a collec- 

 tion of fresh-water algae, consisting of fifteen samples, collected by 

 Dr. Yolz in Sumatra, West Java, Singapore, Bangkok, and the Sand- 

 wich Islands. Of these regions the best known is West Java. Fifty- 

 one novelties are described, and interesting statements are made 

 concerning the Flagellatae and Peridineae, and the composition of the 

 plankton of two lakes. The author prefaces his list by some remarks 

 on the similarity between the fresh-water algae of European and tropical 



* Bull. Soc. Bot. de France, 1906, pp. 390-407. 



t Abb. Nat. Ver. Bremen, x\'iii. (1905) pp. 143-74.^ 



