COSMARIUM. 155 



A large variet} r , almost twice as long as broad, and 

 less deeply constricted than the type ; semicells with 

 truncate or subtruncate apices ; cell-wall densely 

 punctate, often thick. 



Length 98-107 M; breadth 53-66 n; breadth of 

 isthmus 33-43 ju; thickness 38'5-46,u. 



ENGLAND. Helvellyn. Westmoreland ! 



V 



SCOTLAND.--" Pretty common : (Roy fy Bissett). 

 Skye, Inverness ! AY. of Kirkwall, Orkneys ! 



Geogr. Distribution.- -Bornholm. Spitzbergen. Green- 

 land. 



15. Cosmarium Subcucumis Schmidle. 

 (PL LX, figs. 1-3.) 



Cosmarium siibcucumis Scliinidle, Beitr. Algenfl. Schwarzwald. u. Blieineb. 

 1893, p. 98, t. 4, f. 20-22 ; Nordst, Index Desm. 1896, p. 244; West & 

 G-. S. West, Alg. S. England, 1897, p. 485 ; Alga-fl. Yorks. 1900, p. 69. 



Cells large, broadly elliptic, about If to If times as 

 long as broad, deeply constricted, sinus linear and 

 dilated towards the extremities (sometimes slightly 

 open) ; semicells semi-elliptic, basal angles rounded, 

 apex convex or somewhat flattened. Side view of 

 semicell broadly elliptic. Vertical view elliptic, ratio 

 of axes about 1 : 1'5. Cell-wall smooth. Chloroplasts 

 axile, each with two pyrenoids. 



Zygospore unknown. 



Length 54-78 /A; breadth 36-45 /x; breadth of 

 isthmus 15-19 p. ; thickness 23 26 /A. 



ENGLAND.- -Ogden Clough, Ilkley, and Cautley 

 Spout, "W. Yorks ! Eslier West-end and Wimbledon 

 Commons, Surrey ! 



Geogr. Distribution. Germany. Galicia in Austria. 



The British specimens are not precisely like those originally 

 described by Schmidle from Germany. The cells are rela- 

 tively longer and the sinus is generally slightly open. The 

 relative proportion of breadth to length in the British speci- 

 mens is 1 : 1'79; that in the German specimens is 1 : 1*42. 



The species differs from C. Cucumis in its axile chloroplasts, 

 each of which contains two rather large pyrenoids. 



