266 BRITISH DESMIDIACE^E. 



Genus MICRASTERIAS Ag. 

 Micrasterias papillifera Breb. (vol. ii. p. 91). 

 (PL CLXVII, fig. 11.) 



Zygospore compressed, globose in front view, broadly 

 oval in lateral view, with numerous strong spines, 

 simple or slightly furcate at the apex. Diam. zygosp., 

 without appendages, 85 k m ; including appendages, 138^ ; 

 thickness, without appendages, 69 \L ; including appen- 

 dages, 115 y.. 



[The figure of the zygospore on PL XLIY, fig. 7, is not good, 

 and the dimensions for the zygospore given in vol. ii, p. 92, 

 are obviously erroneous. The compressed form of the spore ha& 

 not been previously noted, and the appendages are not identical 

 with those figured by Ralfs.] 



Genus COSMARIUM Corda. 

 Cosmarium diplosporum (Lund.) Liitk. (vol. i, p. 61). 



Cylindrocystis diplospora Lund. Desm. Suec. 1871, p. 83, t. 5, f. 7; W. & 



G. S. West, Brit. Desm. vol. i, p. 61. 

 Cosmarium diplosporum Liitkem. C4attung Cylindrocystis, 1913. p. 227. 



Cosmarium pseudarctoides Strom (vol. i. p. 62). 



Cylindrocystis minutisxinia Turn. Freshw. Alg. E. India, 1893, p. 16, t. 1,. 



f. 24 ; W. & G. S. West, Brit, Desm. vol. i, p. 62. 

 Cosmarium pseudarctoides Strom Alg. Tuddal, 1920, p. 31. 



Strom has observed spores in the cell- wall of this tiny Desmid, 

 and for this reason transferred it to the genus Cosmarium. 

 Liitkemuller (' Gattung Cylindrocystis '). 1913, considered it to 

 be a doubtful species of Cylindrocystis. 



Cosmarium Mooreanum (Arch.) Liitk. (vol. i, p. 80). 



Penium Mooreamon Arch. Descr. New Cosm. etc. 1864, p. 24, t. 1, f. 34-44 ;. 



W. & G. S. W. Brit. Desm. vol. i, p. 80. 



Dysphinctium Mooreanum Liitkem. Gattung Peniinn, 1905, p. 337. 

 Cosmarium Mooreanum Liitkem. Zur. K. Desm. Bohmens, 1910, p. 490. 



