COSMARIUM. 183 



Length 54-00 /x : breadth 48-51 ^ ; breadth of apex 

 about 19-20/u; breadth of isthmus 18-19/x; thickness 

 29-34 /x. 



ENGLAND.- -Westmoreland ! W., JST., and E. Yorks ! 

 Devon (Bennett). Cornwall! (Marquand). 



WALES.- -Moel Siabod, Snowdon, and Yr Orsedd, 

 Carnarvonshire ! Dolgelly, Merioneth ! 



SCOTLAND.- -Ross, Inverness, Aberdeen, Kincardine, 

 Forfar !, Perth, Stirling, Argyll (Roy $' Bissett). 

 Sutherland ! Orkneys ! 



IRELAND.- -Donegal ! Galway ! Kerry! 



Geoc/r. Distribution. Germany. Norway. Sweden. 

 Greenland. Spitsbergen. Nova Zembla. N. Russia. 

 Faeroes. India. 



This variety differs principally from C. Hammeri in its 

 larger size and in the tumid vertical view. It is, however, 

 very variable, especially with, regard to the sides of the 

 semicells and the apex. The latter may he slightly retuse, 

 straight, or convex,, and the apices of the semicells of one 

 individual may differ considerably. 



In Britain it is found mostly in subalpine localities, 

 especially in mountain springs and in the vicinity of dripping 

 rocks. 



We have included in this variety " C. homalodermum var. 

 rotundafum Wille ; ' as the side view of the semicell is some- 

 what variable. Intermediate stages can be met with between 

 a subcircular and an ovate side view. Borgesen also finds 

 this D eg mid to be very variable in the Faeroes, and to reach a 

 leno-th of 70^ and a breadth of 58 /u (vide 'Freshw. Alg. 

 Faeroes/ 1901, p. 222). 



Var. protuberans West & G. S. West. (PI. LXII, 



figs. 24, 25.) 



C. Hammeri Eeinsch. var. "with inflated sides" Wolle, Desm. U.S. 1884, 



t, 18, f . 36-38. 

 C. Hammeri Eeinsch var. protuberans West and G. S. West, Some N". Amer. 



Desm. 1896, p. 246, t. 14, f. 35. 



Cells rather small; vertical view with a median 

 tumour on each side. 



Zygospore globose, furnished with numerous, simple 

 spines, which are dilated at the base. 



