EUASTRUJil . 45 



lobes, and with five granules arranged on a central 

 protuberance. 



Length 36 /x; breadth 22 /*; breadth of isthmus 6 /x. 



ENGLAND. Trelleck Common, Monmouth (Turner). 



Var. cambrense (Turn.) nob. (PL XXXVIII, fig. 10.) 



Euastrum cambrense Turn. Desm. Notes, 1893, p. 343, f. 1. 



Upper lateral lobes furnished with a short, upwardly- 

 directed spine ; with six granules forming a ring on the 

 central protuberance. 



Length 32 /x ; breadth 20 p ; breadth of isthmus 5 /x ; 

 thickness 9*5 p.. 



WALES. Near Dolbadarn Castle, Carnarvonshire 

 (Turner). 



Var. Snowdoniense (Turn.) nob. (PL XXXVIII, 



%. no 



Euastrum Snowdoniense Turn. Desm. Notes, 1893, p. 343, f. 2. 



Cell-wall of lateral lobes and polar lobe thickened at 

 the margin ; apical notch open ; with three small pro- 

 tuberances (?) forming a triangle in the centre of the 

 semicell. 



Length 31 /A; breadth 20 /x; breadth of isthmus 6*5 p.. 



WALES. Snowdon, Carnarvonshire (Turner). 



28. Euastrum erosum Lund. 

 (PL XXXVIII, figs. 12, 13.) 



Euastrum erosum Lund. Desni. Suec. 1871, p. 22, t. 2, f . 6 ; Cohn, Desm. 

 Bongo. 1879, t. 11, f. 12 ; Cooke, Brit. Desm. 1886, p. 77, t, 35, f. 12 ; De 

 Toni, Syll. Alg. 1889, p. 1072; West, Alg. aq. dulc. Lusitan. 1892, 

 p. 1501 ; Eoy & Biss. Scott. Desni. 1893, p. 176 ; Nordst. Index Desm. 

 1896, p. 119 ; West & Gr. S. West, Alga-fl. Yorks. 1900, p. 63. 



Helierella erosa Kuntze, Revis. gen. plant. 1891, p. 898. 



Cells very small, 1| If times longer than broad, 

 deeply constricted, sinus narrowly linear ; semicells 

 somewhat hexagonal, the base broader than the re- 

 maining sides, angles rounded, lower portions of lateral 

 margins parallel and retuse, upper portions converging 



