36 COLLINS AND HEEVEY. 



records for Bohemia "C. geminella Wolle (Hormospora geminella 

 Wolle Bull, of the Tor. Bot. Club 1877)" and describes var. minor. 

 The diameter of cells given for the typical C. geminella, 20-24 m, does 

 not agree with Wolle's figures, 16-21 ^ for Hormospora, 14-16 ix for 

 Cylindrocapsa, but are nearer C. involiita Reinsch, 23-30 /x. Hans- 

 girg's var. minor is said to be 12-15 fi, diam., exceptionally 18-25 n, in 

 very young filaments 9-12 fj., which would certainly include Wolle's 

 C. geminella. On comparing all the descriptions and figures, we can 

 find no real distinction between C. involuta, C. geminella and C. 

 geminella var. minor; and in the Bermuda material we can match 

 practically every figure. We have therefore used the oldest naine. 



Family OEDOGONIACEAE. 

 Oedogonium Link. 



1. Oogonium with a. whorl of conical projections. 3. O. Itzigsolinii. 



1. Oogonium without whorl of projections. 2. 



2. Filaments 14-20 n diam. 1. O. Pringsheimii. 



2. Filaments seldom over 12 ix diam., usually in stellate clusters. 



2. O. consociatum. 



*1. O. Pringsheimii Cramer ex Hirn, 1900, p. 170, PI. XXVII, 

 fig. 155; Collins, 1909, p. 246; P. B.-A., No. 1861. In ditch in Devon- 

 shire Marsh, April, Collins. 



*2. O. consociatum sp. nov. Plate I, figs. 1^; P. B.-A., No. 

 2068. Diocum (?), macrandrium; oogonia solitaria, globosa vel 

 depresso-globosa, operculata, rima mediana vel subsuperiore, angusta 

 sed distincta; oospora globosa vel depresso-globosa, oogonium im- 

 plente, membrana laevi; cellula basali depresso-globosa; cellulis vege- 

 tativis plus minusve distincte clavatis. 



Dioecious (?), macrandrous; oogonia single, globose to depressed- 

 globose, operculate, division median to superior, narrow but distinct; 

 oospore globose to depressed globose, filling the oogonium, membrane 

 smooth; basal cell depressed-globose; vegetative cells more or less 

 distinctly clavate. 



veg. cell, female, 6-12 (20) m diam., 1^ diam. long, 



oog. 28 M " 26-28 M " 



oosp. 26 M " 24-26 M " 



