112 BRITISH DESMIDIACEJG. 



cuneate- quadrate, sides straight or substraiglit and very 

 slightly divergent upwards, basal angles a little rounded, 

 upper angles obliquely truncate, apex truncate and 

 slightly retuse. Vertical view circular or somewhat 

 compressed. Cell-wall smooth. Chloroplasts axile, one 

 in each semicell, with a small central pyrenoid. 



Zygospore unknown. 



Length 14*5-20 //,; breadth 7'5-9'5/x,; breadth of 

 isthmus 5 '5-0 p.. 



ENGLAND.- -Thursley Common, Surrey ! 



Geoyr. Distribution.- -Madagascar, 



Yar. subturgidum West & G. S. West. (PI. LXXIV, 



fig. 14.) 



Cosmarium parvulum Breb. forma, Bohlin, Flor. algol. d'eau douce d. 



Azores, 1901, p. 67, t. 1, f. 30. 

 C. goniodes var. subturgidum West & G. S. West, Alg. N. Ireland, 1902, 



p. 41, t. 2, f. 12. 



Semicells with slightly convex sides and somewhat 

 more retuse apices ; vertical view elliptic-circular. 

 Cells commonly twisted at the isthmus. 



Length 18-19'2/x; breadth 3'6-9'4/x; breadth of 

 isthmus 6*7 ft; thickness 7 '8-8/1. 



ICELAND. Louo'hs Machugh and Masrath. and near 



o o o 



Grlenties, Donegal ! 



Geor/r. Distribution.- -Azores. Australia. 



Var. variolatum West & G. S. West. (PI. LXXIV, 



fig. 15.) 



C. goniodes var. variolatum West & G. S. West, Fresliw. Alg. Orkneys and 

 Shetlands, 1905, p. 23, t. 1, f. 18. 



Cells relatively shorter and commonly twisted at 

 the isthmus ; semicells slightly attenuated, superior 

 angles rounded. Side view of semicell ovate-pyra- 

 midate. Vertical view broadly elliptic. Cell- wall 

 punctulate, punctulations very delicate and distant, 

 6-9 visible in the front view of each semicell. 



Length 20-21-3 p.; breadth 1O6-12'2 /*, ; breadth of 

 isthmus 8'5-8'8 ^ ; thickness 8*5 JJL. 



SCOTLAND. Near Scallowav. Shetlands ! 



