57 



IRELAND. Donegal! Mayo! Gahvay ! Kerry! Down! 

 Armao-h ! Londonderry ! 



CT* *' 



Geoc/r. Distribution.- -France. Germany. Galicia 

 and Austria. Norway . Sweden. Bornholm. Finland. 

 X. Eussia (var.). Iceland. Greenland. Central China. 

 Ceylon. Siam. Singapore. Java. Australia (var.). 

 Xe'w Zealand. Madagascar (var.). E. and Central 

 Africa. Azores. United States. West Indies. 

 Brazil (var.). 



This species is generally distributed and often abundant. 

 It varies much in size and in the form of the basal angles, 

 but always retains its distinctive features. AVe have made 

 no attempt to classify the numerous forms which exist. 



Var. granulatum West. (PL XXXIX, fig. 5.) 



E. denticulatum var. granulatn.n West, Alg 1 . W. Ireland, 1892, p. 141, t. 20, 

 f. 17. 



Superior angles of semicells without an acute tooth ; 

 cell- wall finely granulate all over the surface. 



Length 18 p.; breadth IS IJL; breadth of isthmus 

 4 /A; thickness 9 p.. 



IRELAND. Ballynahinch, Galway ! 



33. Euastrum minutissimum nob. 

 (PL XXXVIII, fig. 37.) 



Euastrum exile Turn. Desm. Notes, 1893, p. 346, f. 21 [not E. exile Josh. 



1886]. 



Cells very minute, almost twice as long as broad, 

 deeply constricted, sinus narrowly linear ; semicells 

 oblono'-pvramidate, basal angles rounded, lateral mar- 



i A </ 



gins retuse, apex rounded, with a median, somewhat 

 open notch. Side view of semicell ovate-pyramidate, 

 apex rounded, lateral margins retuse. Cell-wall 

 smooth. 



Zygospore unknown. 



Length 15 /x; breadth 8 (JL; breadth of isthmus 3 ^; 

 thickness 4 p,. 



^VALES. Snowdon, Carnarvonshire (Turner). 



We have never observed this minute species, but have been 



