170 SCIENCE PROGRESS 



BOTANY 



AlgSB. Vol. I. Myxophyceae, Peridinieae, Bacillarieae, Chlorophycese, together 

 with a brief summary of the occurrence and distribution of Fresh-water Algae. 

 By G. S. West, M.A., D.Sc, A.R.C.S., F.L.S. [Pp. viii + 475, with 271 

 illustrations.] (Cambridge : at the University Press, 1916. Price 255-. net.) 



The need has long been felt for a text-book on the algae that embraced both 

 fresh-water and marine representatives, whether British or foreign, and the present 

 volume is the first of a two-volume work that aims at covering this wide field. 

 The inclusion of a section on the Peridinieae is a feature at once novel and 

 welcome, and we cannot but regret the author's decision to omit any account of the 

 Flagellata. Our greatly augmented knowledge of this group in recent years has 

 only served to emphasise its importance in phylogenetic considerations, and the 

 significance of many features presented by the lower algae can scarcely be appre- 

 ciated without some acquaintance with the lines of evolution on the Flagellata. 



The classification adopted in the present work is considerably modified from 

 that in the author's treatise on British Fresh-water Algce. Thus the Chlorophy- 

 ceae are subdivided on the lines indicated by Bohlin and elaborated by Blackman 

 and Tansley. 



Following Pascher, three orders are recognised in the Heterokontae, viz. the 

 Heterococcales comprising the unicellular and colonial forms, the Heterotrichales 

 comprising filamentous species, and the Heterosiphonales, with the single genus 

 Botrydium. 



The account of the Cyanophyceae contains a useful resume of modern work 

 upon the cytology of the group and an interesting summary of the conflicting views 

 regarding the nature and function of the heterocyst. The view is expressed that 

 in the living members of the group "the heterocysts appear to have no other func- 

 tion than that of limiting either the hormogones or filaments," but the method of 

 occurrence in Nostochopsis and Spratt's observations on Anabcena cycadearum 

 suggest that the heterocyst may phylogenetically be a gonidangium. 



Schiitt's main divisions of the Bacillarieae into Centricae and Pennatae are 

 maintained, but the latter group is subdivided on Forti's plan into mobile and non- 

 mobile species. 



The literature on the causes of movement in Diatoms is briefly reviewed, and 

 an excellent account is given of Miiller's hypothesis, which regards these spon- 

 taneous movements as due to the protoplasmic currents circulating in the raphe. 



A very interesting chapter treats of the ecology and distribution of algae, but 

 the value of the habitat lists would have been greatly enhanced had they been 

 accompanied by a fuller discussion of the factors involved and a more complete 

 account of the work that has recently been accomplished in this direction. More- 

 over, the biotic relations have scarcely, we think, received the attention they 

 deserve. 



Mention should be made of the useful bibliographies appended to each of the 

 main divisions of the subject-matter and which should prove valuable alike to 

 student and teacher. Also there are numerous excellent figures of which more 

 than half are examples of the author's own inimitable draughtsmanship. 



In view of Prof. West's wide experience of algae from all parts of the world 

 we cannot but feel that a more philosophical and less taxonomic treatment of his 

 subject would have added greatly to the value of the work. 



Prof. West has, however, undoubtedly supplied a real need and filled a 

 long-standing lacuna in our algological literature. We nevertheless fear that the 



