NETRIUM. 65 



ENGLAND. Only abundant in boggy and peaty dis- 

 tricts. Cumberland! Westmoreland ! (Ralfs). Yorks ! 

 Lancashire ! Cheshire (Roy). Leicester (Roy). War- 

 wick (THY/*). Cambridge! Gloucester (Ralfs). Essex! 

 Kent! Surrey! Hants! Devon! (Bennett). Corn- 

 wall! (Ralfs). 



WALKS. General and often abundant; at 2,700ft. 

 on Glyder Fawr, Carnarvonshire ! 



SCOTLAND. General and abundant ! Zygospore 

 from Cambus O'May, Deeside, Aberdeen (Roy $' 

 fiissett). Common in the Outer Hebrides! Orkneys! 

 Shetlands ! 



IE EL AND. General and abundant ! 



Geoc/r. Distribution. Generally distributed in Europe. 

 Faeroes. India. Ceylon. Siam. Java. Central 

 China. Japan. Australia. New Zealand. Azores. 

 United States. British Guiana. Brazil. 



This Desmid exhibits considerable variation in form and 

 size, and the distinction between it and Peniuin lamellosum 

 completely breaks down on the careful examination of numer- 

 ous specimens. Particularly is this the case with regard to 

 the pure gatherings which can often be made in peaty 

 districts. It is frequently attenuated nenr the apices. 



Var. constrictum nol. (PL VI, fig. 17.) 



Penium Digitus var. constrictum West, Alt* 1 . W. Ireland, 1892, p. 127 ; 

 West & G-. S. West, Alg. S. England, 1897, p. 479 ; Freshw. Alg. Ceylon, 

 1902, p. 134. 



Cells 6-8 times longer than their diameter, gently 

 narrowed in the median portion. 



Length 353-405 /u ; max. breadth 55-65 ^ ; breadth 

 in middle of cells 47-55 /u. 



ENGLAND. New Forest, Hants ! 



SCOTLAND. New Galloway, Kircudbright ! Moidart, 

 Inverness ! 



IRELAND. Lakes, from Clifden to Roundstone, 

 Galway ! 



Geogr. Ditstribuion. Lapland in Russia. 



5 



