EUASTBUM. 23 



of four, a median row of three, then a row of four 

 across the upper part of the lateral lobes. Cell-wall 

 punctate. 



Zygospore unknown. 



Length 72 /x ; breadth 45 /x ; breadth of isthmus 15 p.. 



EXGLAXD. Westmoreland (Rolfs). Strensall Com- 

 mon, X. Yorks ! 



IRELAXD. Ballvnahinch, G-alwav ! 



i ^ .' 



Geogr. Distribution. France. United States. 



We have only seen this Desmid on two occasions and have 

 not vet succeeded in obtaining side or vertical views. It 



t 



may only be a variety of E. sinuosum, but this point cannot 

 well be decided until the other views have been obtained. 



11. Euastrum aboense Elfv. 

 (PI. XXXVI, figs 5, 6.) 



Euastrum aboense Elfv. Anteck. Finska Desm. 1881, p. 7, t. 1, f. 2 ; De 



Toni, Syll. Alg. 1889, p. 1103 ; Boy & Biss. Scott, Desm. 1894, p. 175 ; 



Kordst. Index Desm. 1896, p. 36 ; West & G. S. West, Notes Alg. Ill, 



1903. 

 E. inerme (Ealfs) Lund. var. aboense Eacib. Xonn. Desm. Poloii. 1885, 



p. 92. 

 Helierella aboensis Kuntze, Bevis. gen. plant. 1891, p. 898. 



Cells small, about 14- times longer than broad, 

 very deeply constricted, sinus narrowly linear with 

 a slightly-dilated extremity ; semicells pyramidate- 

 rounded (faintly subrect angular), lateral margins sin- 

 uate, with two shallow hollows and a somewhat broad 

 rounded projection in between ; apex subtruncate with 

 rounded angles and a narrow median incision ; semi- 

 cells with a slight depressed protuberance above the 

 isthmus and two others across the centre, also with 

 11-13 conspicuous scrobiculations disposed more or 

 less in a regular pattern across the broad part of the 

 semicell. Side view of semicells quadrate at the base, 

 with rounded angles and retuse sides ; upper portion 

 shortly pyramidate with a rounded-truncate apex. 

 Vertical view elliptic, with two slight protuberances 

 in the middle of each side. 



Zygospore unknown. 



