COSMARIUM. 227 



butioii in tlie British Islands, occurring mostly in boo*s and at 



v O 



the weedy margins of lakes. Tt exhibits considerable varia- 



*/ 



tion in the creiiation of the lateral margins of the semicells 

 and in the extent of the granulation. We have not attempted 

 to discriminate between those forms exhibiting only minor 



/ 



differences, as so many intermediate states exist. 



Var. Novae-Sylvse West & G. S. West. (PI. LXXXVI, 



figs. 5, 6.) 



C. Blyttii Wille var. Novze-Sylvze West A: a. S. West, Ate. S. England. 

 1897, p. 489, t. 6, f. 10. 



Cells a little larger, often more or less oblonsr-sub- 



CJ O 



rectangular, lateral crenations more prominent and 

 truncate, usually with only one series of granules 

 within the margin, and with an arc of 4 small granules 

 on the lower side of the central granule. 



o 



Length 2O5-22/i; breadth 17*5-19 ^: breadth of 

 isthmus 5'5/x; thickness 10 p.. 

 ENGLAND.- -Xew Forest, Hants ! 



This variety occurred in abundance in one of the Sphagnum- 

 bogs of the Xew Forest. It should be compared with C. 

 Blyttii subsp. Eoffii Borg. ('Bornholni. Desm.-hV 1889, p. 144, 

 t. 6, f. 5), from which it differs in being proportionately 

 longer, in its more pronounced lateral crenations,, and in the 

 central granules of the semicells. 



199. Cosmarium sexnotatum G-utw. 

 (PL LXXXVI, fig. 7.) 



Cosmarium sexnotatum Gutw. in Nuova Notarisia, 1892, p. 19 : Flor. 

 Glonow Galic. 1892, p. 125, t. 3, f. 7. 



Cells small, almost 1^ times as long as broad, 

 deeply constricted, sinus narrowly linear ; semicells 

 subsemicircular with a flat base, basal angles sub- 

 rectangular, sides convex and 4-crenate, apex sub- 

 truncate (slightly convex) and 4-crenate, with a single 

 series of small granules within the margin, and with 

 an interrupted inner series consisting of 3 within the 

 apex and 3 within each lateral margin, in the centre 

 above and rather close to the isthmus with a transverse 



