94 BRITISH DESMIDIACK.K. 



which are subtruncate and slightly thickened ; cell- 

 wall regularly and somewhat sparsely punctate ; 

 chloroplasts with 9 or 10 longitudinal plates (or ridges) 

 and one large pyrenoid. 



Zygospore unknown. 



Length 92-95 p ; breadth 45 fi. 



KNGIAND. Near Bowness, Westmoreland (Bixxctt). 



SCOTLAND. Near Tain, Koss; Slewdruni, Aboyne, 

 Dawan, Presswhin, Dalbagie, Glen Clunie, Aberdeen ; 

 Scolty Dam, Curran, Bishop's Dam, Kincardine; Glen 

 Clova, Glen Dole, Forf ar ; Brecklin, Coilantogle, Perth 

 (Buy fyBissett). 



( 1 <'<></ r. Distribution. Java (var.). 



22. Penium cucurbitinum Biss. 



(PL IX, figs. 13, 14.) 



Peninm cucurbitinum Biss. Desm. Windermere, 1884, p. 197, t. 5, f. 7; 

 Cooke, Brit. Desm. 1886, p. 40 ; West, Alg. N. Yorks. 1889, p. 291 ; 

 Mo;. N. Wales, 1890, p. 280 ; Alg. W. Ireland, 1892, p. 128 : Alg. Eng. 

 Lake Distr. 1892, p. 721 ; Roy & Biss. Scott. Desm. 1S94, p. 251 ; 

 Nordst. Index Desm. 1890, 'p- 9 2 ; West & G. S. West, Alg. S. 

 England, 1897, p. 479 ; Alga-fl. Yorks. 1900, p. 47. 



Cells of medium size, subcylindrical, rather more 

 than 2^- times longer than their diameter, slightly 

 tapering towards the apices which are broadly rounded, 

 with a slight median constriction ; cell-wall minutely 

 and somewhat sparsely punctate ; chloroplasts with 

 about six longitudinal ridges and one large pyrenoid. 



Zygospore unknown. 



Length 64-83 ^ (rarely up to 90 /u) ; breadth 2i.5-oo/u 

 (rarely up to 3 5 /u). 



ENGLAND.- Near Bowness! (7>/.s-xr//), Louo-hries: ! , 



/ 7 O o o 



Helvellyn ! , trough at Ambleside, Westmoreland ! 

 Ogden Clough, Shipley Glen, Holden Ghyll near 

 Keighley, Ilkley, Penyghent, Widdale Fell, W. Yorks ! 

 Riccall Common, E. Yorks ! Epping Forest, Essex ! 

 Thursley Common, Surrey ! 



WALES. Llyn-an-afon, Y Foel Fras, and Snowdon, 

 Carnarvonshire ! 



