COSMARIUM. 125 



Zygospore unknown. 



Length 90-119 /A ; breadth 68-75 p. ; breadth of 

 isthmus 27 /x,; thickness 48 //,. 



SCOTLAND.- -Falls of Connon, Ross; south of Port- 

 lethen, Kincardine; Fintray Hills, Stirling (Roy $ 

 Bis sett). 



Geogr. Distribution.- -Italy. Sweden (Gotland). 



We have not seen this species, but it appears to have a cell- 

 wall like that of C. pachydermum Lund. Nordstedt has 

 suggested (from an inspection of De Notarises figures) that the 

 chloroplasts are parietal. 



135. Cosmarium quadrimamillatum West & G. S. 



West. 



(PI. XCIII, fig. 3.) 



Cosmarium quadrimamillatum West & Gr. S. "West, Notes Alg. Ill, 1903, 

 p. 9 (sep.), t. 446, f. 12 ; Freshw. Alg. Orkneys and Shetlands, 1905, 

 p. 22. 



Cells small, about as long as broad or a little 

 broader, deeply constricted, sinus narrowly linear with 

 a dilated extremity; semicells transversely subrect- 

 angular or elliptic-rectangular, basal angles slightly 

 rounded, sides subparallel or upwardly divergent, 

 slightly concave, superior angles minutely but dis- 

 tinctly mamillate, apex broadly elevated and slightly 

 subconvex, in the centre of each semicell with a sinsrle 



7 o 



large granule, and with a smaller granule just within 

 each mamilla. Side view of semicell subcircular, with 

 a granule at the middle on each side. Vertical view 

 elliptic, with a large median granule at each side, and 

 a smaller granule at each side of the poles. Chloro- 

 plasts axile, one in each semicell, with a large central 

 pyrenoid. 



Zy go spore unknown. 



Length 23-27 /x; breadth 23-27*5 ^; breadth of 

 isthmus 7-8'6/>c; thickness 13*5 /x,. 



ENGLAND. In ditches near the Lizard, Cornwall ! 



SCOTLAND. In a ditch, Bressay, Shetlands ! 



