74 SUMMAKY OF CURKEJST RESEARCHES RELATING TO 



polymorphism of Eaastrum Didelta is described and discussed. The 

 forms with divergent, young' semi-cells are called by the author "mixed 

 forms." Nine intermediate forms are figured. These are followed by 

 the monsti'osities. The material examined came from Col des Gets, 

 Piora and Bisanne. E. S. Ct. 



Contribution to a Study of the Desmid Flora of Switzerland. 

 — F. DuCELLiEU {Bull. Soc. hot. Geneve, 19 IC, 8. 2nd Ser., 2'.)-79, figs, 

 in text ; see also hot. Cenfralbl., 1918, 138, 38). An addition to 

 previous work on the subject by the author. A large number of species 

 and groups are discussed critically and figured in detail ; and one new 

 variety and many new forms are described. The Col du Simplou is rich 

 in species of Penmm. E. S. G. 



New Species of Spirog-yra. — Wiltjam J. Hodgetts {Annals of 

 Botany, 1920, 34, 519-24, 1 pi. and 5 figs.). A description of 

 Spirogyra colligata, a new species from King's Norton, Worcestershire, 

 with special discussion of th(i remarkable clamp-connections which 

 develop between the contiguous pairs of cells of the filament. These 

 clamps are short open cylinders, bisected by a median septum or 

 diaphragm, and appearing like the letter H in optical longitudinal 

 section. In each compartment of the clamp is firmly set the end of an 

 adjacent cell. Conjugation in this species is both scalariform and 

 lateral, and also terminal (apparently a unique feature), A. Gepp. 



Studies in the Conjugation of Spirogyra ternata. — Mabel L. 

 Merriman {Bull. Torrey Bot. Club, 1920, 47, 9-20, 3 figs.). An in- 

 tensive study of one species of Spiroyyra, with tables of measurement of 

 successive cells of two conjugating, filaments, male and female, showing 

 the dimensions of three sorts of cells — conjugating, tumid (but not 

 conjugating), non-conjugating (vegetative) — and their ratios to one 

 another ; and showing also the measurements of the outer and inner 

 walls of the cells, where the curvature of the filaments was greatest. 

 This is a preliminary paper ; and all deductions as to potency of cells, 

 formation of conjugating tubes, and other problems are reserved for a 

 future paper. A. G. 



Flagellates and Algse of the District around Birmingham. — 

 W. B. Grove, B. Muriel Bristol and Nellie Carter {Journal 

 of Botany, 1920, 58, Supplement III., 55). A list compiled from 

 records made by the late Prof. G. S. West during the years 

 1906-1919, together with recent collections and determinations by Mr. 

 W. J. Hodgetts. The list is extensive, and comprises 192 genera, 

 736 species, and numerous varieties. Subdivided the numbers are as 

 follows :— Flagellata (13 gen., 33 sp.) ; Myxophycese (27 gen., 85 sp.) ; 

 Peridiniea3 (5 gen., 14 sp.) ; Bacillarie£e (35 gen., 154 sp.) ; Chloro- 

 phycese (1 12 gen., 450 sp., inclusive of 22 gen. and 196 sp. of Desmidiacea3). 



• A. G. 



Fresh-water Algae of Devonshire. — G. T. Harris {Report and 

 Trans. Devonshire Association, Plymouth, 1920, 52, 263-75). A list 

 of thirty-five Myxophycea?, eighty-two Chlorophycete, two Rhodophycefe, 



