DIE SUSSWASSER-FLORA DEUTSCHLANDS, ETC. 363 



in describing the plates composing the cell-wall is out-of-date and 

 unsatisfactory. The author accepts Klebs' proposals of 1912, 

 although the reasons for the changes suggested by Klebs are by 

 no means clear or sufficient. The Gymnocliniaceas (including 

 Glenodinium) is renamed the " Kyrtodiniaceae " and the Peridini- 

 aceae (excluding Glenodinium) is renamed the " Krossocliniaceae," 

 but these new names are really unnecessary. The figures in some 

 instances, especially of the species of Cerastium, are rather poor. 



Heft 9. Zygnemales, von O. Borge unci A. Pascher. The 

 special systematic section by Dr. Borge is a good summary of the 

 Zygnemaceae of the three countries under consideration, but the 

 descriptions are sometimes too brief, and the entire absence of 

 critical remarks detracts considerably from the value of what 

 otherwise might have been a most useful work. The figures in 

 many cases are not very good, and they are mostly too scrappy 

 to be really of value in identifying species. Debary's genus 

 Zygogonium (not the Zygogonhmi of Kiitzing), recently upheld by 

 Wille (1909), is here accepted by both authors, although it appears 

 to be founded upon two examples of monstrous conjugation of 

 Zygnema ericetorum. The description of this alga as having 

 "1 axiles Chromatophor mit 1 Pyrenoid" is also wrong. 



Heft 10. Bacillariales (Diatomea), von H. v. Schonfeldt. This 

 little volume of 187 pages is an attempt to condense the diatom- 

 flora of three countries into a very small space. It may enable 

 the student to identify the larger and commoner types of diatoms, 

 but he would find himself in great difficulties with many of the 

 smaller and more critical species. The figures cannot be described 

 as very good, and they are rather too small. Moreover, few, if 

 any, appear to be original. Good figures of the common forms of 

 fresh-water diatoms yet remain to be published. 



G. S. West. 



BOOK-NOTES, NEWS, &c. 



At the meeting of the Linnean Society on 6th November, Mr. 

 H. Hamshaw Thomas, on behalf of himself and Miss Nellie 

 Bancroft, explained the main points of a joint paper as follows : — 

 An investigation of the cuticles of some recent and fossil Cycaclean 

 fronds was undertaken with a view to determining the probable 

 relationships of the modern group to the Mesozoic Cycadophyta. 

 The value of the epidermal and stomatal characters in classifi- 

 cation and comparison is indicated by the fact that each living 

 genus possesses a characteristic cuticular structure ; the guard- 

 cells of the stomata, however, conform to a constant ground-plan. 

 In the case of the fossil fronds, the stomata are constructed on 

 very similar lines to those in the recent forms, though they differ 

 in one or two directions. These fronds fall into two groups — 

 (1) Bennettitales, containing the majority of the Mesozoic fronds 

 previously considered as Cycadean ; (2) Nilssoniales, including 

 such fronds as Nilssonia, Ctenis, and Ptilozamites. The first 

 group is characterized by the possession of epidermal cells with 

 sinuous walls, while the stomata, which have characteristically 



