292 THE JOURNAL OF BOTANY 



is an immense improvement upon Chodat's Algues Vertes de la 

 Suisse, which forms part of the same series. 



The volume commences with a brief historical account of the 

 work on Swiss Diatoms, including a list of the literature, in which 

 reference is made to the distribution of Diatoms in that country. 

 This is followed by an account of the methods of collection, 

 preparation, mounting, and labelling of specimens, &c. A list of 

 the principal systematic works consulted during the preparation 

 of the volume is then given, and a very brief description of the 

 structure of Diatoms is prefixed to the systematic account, which 

 is the main part of the volume. 



The classification adopted follows in the main that originally 

 put forward by Schiitt in Engler & Prantl's Pflanzenfamilien. 

 Useful keys are given to the families, genera, and species. The 

 general typography is clear and good, and the specific descriptions 

 are as concise as is consistent with the proper enumeration of dis- 

 tinctive characters. The plates are mostly very well executed, 

 but the figures of the various species of Nitzschia are not very 

 clear. In fact, there is still room for a work in which the 

 numerous common species of this genus will be accurately figured 

 in both valve and girdle aspects. The figures of Cymatopleura 

 Solea are not good, and do not show the marginal beading of the 

 valves very well. Moreover, the girdle view of this species, with 

 its characteristic alternating undulations on the two sides, should 

 be figured. One notices with pleasure that the author adopts the 

 genus Gyrosigma Hassall (1845) instead of the more usual Pleuro- 

 Sigma W. Sm. (1853). 



As would be expected, there are numerous species of •' Cy7n- 

 bella'' in the Swiss mountains, and the new figures of these 

 species will be of great use to future workers. The author would, 

 however, have been more consistent had he adopted the genus 

 Cocconema Ehrenb. (1829), which is one year previous to, and also 

 strictly synonymous with, Cymhella Ag. (1830). The curious 

 absence of Asterionella formosa from the Swiss Diatom-flora is 

 certainly worthy of mention. 



The author describes thirteen new species and fifty- seven new 

 varieties, and Latin diagnoses are given of all these new forms in 

 an appendix. One of the proposed new species, Synedra Schroeteri 

 Meister (1912), is most probably identical with Synedra Lemmer- 

 mannii W. & G. S. West (1906), which was originally described 

 from the plankton of Lough Corrib in Gal way. 



The twelfth contribution of Dr. Achille Forti's series deals 

 with the classification of Diatoms, more particularly those which 

 exhibit no movements. Forti's classification is based primarily 

 upon the fact that some Diatoms exhibit spontaneous movements, 

 whereas others do not. The author accepts 0. Miiller's interpre- 

 tation of the movements as being due entirely to protoplasmic 

 currents circulating in the raphe, and therefore the primary divi- 

 sion he adopts separates all those Diatoms which possess a raphe 

 — whether perfectly or imperfectly developed — from those which 

 do not. The two sections are defined as follows : — 



