EUASTROI. 67 



Var. alatum Wolle. (PI. XL, fig. G.) 



E. ver.'ucosum var. alatum Wolle, Desm. U.S. 1884. p. 101, t. 26, f. 4 ; De 

 Toni, Syll. Alg. 1889, p. 1067 ; Anderss. Sverio-. Chlor. 1890, p. 10 ; 

 Gutw. Flor. Gloii. Okolic Lwowa, 1891, p. 72 ; West, Alg. W. Ireland, 

 1892, p. 136. 



Cells with the outer half of the sinus open and then 

 partially closed again, causing the basal angles of the 

 semicells to have a hooked appearance. 



Length 84-110 /x; breadth 71-108 /x; breadth of 

 isthmus 22 ft;, thickness -11 p.. 



SCOTLAXD. Tarbert, Harris, Outer Hebrides ! 



IRELAND. Cloonee Lough, Kerry ! 



Geogr. Distribution. Gralicia in Austria. Sweden. 

 X. Russia. United States. 



Var. planctonicum West & Gr. S. West. (PL XL, 



fig. 7.) 



E. verrucosum var. jolanctonicum West & G. S. West, Scott. Freshw. 

 Plankton, I, 1903, p. 537, t. 15, f. 4. 



Cells with a widely open sinus ; lateral lobes entire, 

 obtusely conical. 



Length 90 /x ; breadth 91 /x; breadth of isthmus 19*5 /x. 



SCOTLAXD. In the plankton of Lochs Ruar and Xan 

 Cuinne, Sutherland ! (.7. Murray). 



This remarkable variety occurred plentifully in the plankton 

 of Loch Ruar. A few specimens were observed in which 

 there was a slight indication of the presence of the superior 

 lateral lobules. 



39. Euastrum occidentale West & Gr. S. West. 



(PL XXXIX, fig. 20.) 



? Cosmarium protractum Wolle, Desrn. U.S. 188-1, p. 83, t. 17, f. 27, 28 



[not C. protractum (Nag.) De Bary, 1858]. 

 Euastrum verrucosum Ehrenb. var. simplex Josh. New and Rare Desm. 



1885, p. 34, t. 254, f . 2 ; West, Alg. N. Wales, 1890, p. 287. 

 E. verrucosum Ehrenb. var. simplex Josh, forma tumescens Turn. Freshw. 



Alg. E. India, 1893, p. 74, t. 11, f. 9*. 

 E. occidentale W T est & G. S. West, Some Desm. U.S. 1898, p. 293. 



Cells of medium size, about 1J times longer than 

 broad, deeply constricted, sinus narrowly linear with 

 a dilated apex ; semicells truncate-pyramidate, broadly 



