54 BRITISH DESMIDIACE.E. 



Basal angles of semicells triundulate or slightly 

 trier en ate. 



Length 22-29 p,; breadth 14-20 /*; breadth of 

 isthmus 4'8-5'5 /x; thickness 11-12 p.; diam. zygosp. 

 without spines 27-29 /*,; length of spines 3'8-9'5 p.. 



ENGLAND. Helvellvn, Westmoreland ! Mossdale 



/ 



Moor, Widdale Fell, N. Yorks (with zygospores) ! 



SCOTLAND. Moidart, Inverness ! Khiconich, Suther- 

 land ! Near Kirkwall, and Hoy, Orkneys ! 



WALES. Bog below Llyn Idwal, Carnarvonshire ! 



IRELAND. Near Foxford, Mayo ! 



Geogr. Distribution. Germany. Galicia in Austria. 

 Lappmark in Sweden. 



Var. retusum West. (PI. XXXVIII, fig. 34.) 



E. binale var. retusum West, Alg. Engl. Lake Distr. 1892, p. 723, t. 9, f. 0. 



Basal angles of semicells obliquely truncate-retuse ; 

 apex broadly truncate-retuse; cell-wall finely granu- 

 late-punctate; central protuberance broadly rounded 

 and granulate. 



o 



Length 27 p.; breadth 21 /x; breadth of isthmus 8 /^; 

 thickness 12 p. 



ENGLAND. Kirk Fell, Westmoreland ! 



Var. elobatum Lund. (PI. XXXVIII, fig. 35.) 



E. binale var. elobatum Lund. Desui. Suec. 1871, p. 23, t. 2, f . 7 ; Cooke, 

 Brit, Desm. 1886, p. 75, t. 35, f. 8; Lutkeru. Desm. Attersees, 1893, 

 p. 559; West & G. S. West, Alg. S. England, 1897, p. 484; Alga-fl. 

 Yorks. 1900, p. 64 ; Alg. N. Ireland, 1902, p. 29. 



E. elobatum (Lund.) Roy & Biss. Scott. Desm. 1893, p. 176. 



Cells hexagonal; semicells pyramidate, apices as in 

 type, lateral margins with a median undulation between 

 the base and the apex. 



Length 21-28 //,; breadth 15'5-2O5 p.; breadth of 

 isthmus 4-5 p.; thickness 11 p.. 



ENGLAND. Bassenthwaite Water and Borrowdale, 

 Cumberland ! Helvellyn and Brothers Water, West- 

 moreland ! Penyghent, W. Yorks ! Strensall Common, 

 Mickle and Cronkley Fells, N. Yorks ! Biccall Common, 



