VI PREFACE. 



most cases from material identified by Professor West ; 

 these are distinguished in the description of the plates 

 by an asterisk. As a last resource the figures of previous 

 authors have been copied. 



Professor West's drawings and a list of British and 

 foreign localities for Desmids were the only material 

 left by the Wests on which the remainder of the work 

 could be based. For inaccuracies in the diagnoses or 

 remarks the writer must take entire responsibility. 

 Whilst she has attempted to embody in these remarks 

 all that has been previously published concerning the 

 various species and, in addition, has sometimes included 

 her own original observations, she can only regret that 

 the information she is able to give is so meagre and 

 incomplete in comparison with what it might have been if 

 Dr. West had not prematurely died ; for it is impossible 

 that work resulting from a six or eight years' know- 

 ledge should form a worthy conclusion to that started 

 on the basis of a life-long study. 



Undoubtedly, many students when studying the 

 numerous species of the difficult genus Staurastrum, will 

 be especially disappointed at being deprived of the experi- 

 ence of our two great algologists. The arrangement into 

 the main sections E, F, G, etc., adopted by the writer 

 is, on the whole, the provisional one prepared by the 

 Wests for the classification of the species of this genus 

 and outlined by them in Vol. IV. A few alterations 

 were made when the writer could not reconcile the 

 structure of the species concerned with the characters of 

 the group. These include the removal of St. pungens 

 and St. Simonyi from Section E to Section F, St. 

 forficulatum from Section I to Section J, and St. 

 aciculiferum from Section J to Section I. The writer 

 realises that the arrangement of the species within each 



