34 BEITISH DESMIDIACE^l. 



Zygospore unknown. 



Length 72 /u ; breadth 8^; breadth of apices 5-0 JH. 



The typical plant has not been found in Britain ; it is only 

 known from Nova Zembla, Siberia, and Gralicia in Austria. 



Forma minor n<>l. (PI. I, fig. 18.) 



Gonatozygon Kjellmani, forma West, Alg. Eng. Lake Distr. 1892, p. 718. 



Cells rather smaller and straight. 

 Length 58 /u ; breadth 6-0*5 /u. 

 ENGLAND. Borrowdale, Cumberland ! 



This rare species has been placed by Raciborski as a variety 

 of G. Brebissonii, but we think it possesses characters which 

 easily distinguish it from that species. It is a much shorter 

 species than G-. Bn'bissomi, being' relatively much wider, the 

 apices are not so rounded, and the granulation is much liner. 



4. Gonatozygon pilosum Wolle. 

 (PI. I, figs. 19, 20.) 



Gonatozygon pilosum Wolle, in Bull. Torr. Bot. Club, 1882, p 27, t. 13, 

 f. 16 ; Desm. U.S. 1884, p. 32, t. i, f . 2 ; West, Alg. N. Wales, 1890, p. 282 ; 

 West & G-. S. West, Freshw. Alg. Ceylon, 1902, p. 133. 



Cells 12-20 times longer than their diameter, cylin- 

 drical ; apices truncate, not at all or very slightly 

 dilated ; cell- wall more or less densely clothed with 

 small, straight, hair-like spines. Pyrenoids about six 

 in each chloroplast. 



Zygospore unknown. 



Length 17 7-300 ji- breadth (without spines) 1O5- 

 15 /j. ; length of spines 2*5-5 /*. 



ENGLAND. Skip with Common, E. Yorks ! 



WALES. Capel Curig, Carnarvonshire ! 



Geogr. Distribution. India. Ceylon. Java. United 

 States. 



This is a rare species, resembling G. monotsenium in the form 

 of its cells, which are cylindrical and sometimes have slightly 

 dilated apices. It is distinguished by the dense covering 1 of 

 fine, stiff s]>im-s. 



