44 BRITISH DESM1DIACK.E. 



Oeogr. Di-stiibntion-.- -France. Germany. Poland. 

 Austria. Italy. Norway. Sweden. JN". and S. 

 Russia. Xova Zembla. United States. India. 



This rather rare Desmid requires further investigation, 

 especially with regard to the nature of the chloroplasts. It 

 is not at all certain in the present state of our knowledge 

 whether it should be placed in the genus Cosmarium or in the 

 genus Penium. 



248. Cosmarium subcylindricum West. 

 (PI. XCIV, fig. 8-.) 



Cosmarium subcylindricum West, Alg\ Eng-1. Lake Distr. 1892. p. 728, t. 9, 

 f. 22 ; Nordst. Index Desm. 1896, p. 244. 



Cells small, about 1J times longer than broad, 

 slightly constricted ; semicells semi-elliptic, with the 

 sides almost straight. Cell-wall densely granulate, 

 granules small and indefinitely disposed, with a single 

 transverse ring of larger granules at the base of each 

 semicell and immediately next the isthmus. Vertical 

 view circular. 



Zygospore unknown. 



Length 37/x; breadth 21 //, ; bread tli of isthmus 

 18 p.. 



ENGLAND.- -Loughrigg, Westmoreland ! 



This Desmid differs from Cosmarium cylindricum in the 

 shape of its semicells, especially the rounded poles, in the 

 irregular arrangement of the small granules, and in the ring 

 of larger granules at the base of each semicell. We have only 

 seen it on one occasion. 



ADDENDA TO GENUS COSMARIUM. 



24V). Cosmarium basilicum G-. S. West. 

 (PI. GUI, fig. 1.) 



Cosmarium basilicum G. S. West, Alga-fl. Cambr. 1899, p. 218, t. 396, f. 7 ; 

 Norclst. Index Desmid. Suppl. 1908, p. 29. 



Cells of medium size, about 1J times longer than 

 broad, deeply constricted, sinus narrowly linear with 



