Myxophyceae 45 



102. Merismopedium tenuissimum Lemmermann. Beitr. Kenntn. Plank- 



tonalgen. Bot. Centralb. 76: 154. 1898. De Toni. Syll. Algar. S: 

 108. 1907. 



Snow. The Plankton Algae of Lake Erie. U. S. Fish Comm. Bull, for 

 1902. 22: 392. 1903. 



Plate II. fig. ZT. 



Colonies quadrangular, free-floating, containing sixteen cells; cells 

 1.3-2 mic. in diameter, somewhat spherical, crowded; cell contents pale 

 bluish green. 



Ohio. Plankton. Put-in-Bay, Lake Erie. (Snow). 



Genus EUCAPSIS Clements and Shantz. 

 Minn. Bot. Studies. 4: 134. 1909. 



Colonies cubical, usually consisting of 32-128 cells, but ranging from 

 8-512 cells, free-floating; tegument uniform, colorless, gelatinous; cells 

 spherical, sometimes elliptical or flattened by mutual pressure, forming 

 cubical families; cell contents finely granular, blue-green; reproduction by 

 cell division in three planes. 



103. Eucapsis alpina Clements and Shantz. Minn. Bot. Studies. 4: 134. 1909. 



Plate II. fig. 38-40. 



Colonies 30-80 mic. in diameter, usually containing 32-128 cells, cubical, 

 free-floating; tegument colorless; cells 6-7 mic. in diameter, spherical, more 

 rarely elliptic, in cubical families; cell contents blue-green. 



Colorado. Alpine pond on Bald Mountain (12,000 feet). September 

 1904. (Shantz). 



Genus ONCOBYRSA Agardh in Flora. 10: 629. 1827. 



Colonies cushion-like, hard, leathery, adherent; sheaths thick, gelat- 

 inous, confluent; cells spherical or elongated, usually regularly arranged 

 in radial rows; cell contents blue-green or violet. 



I Cells pale blue-green, sometimes violet O. rivularis 



II Cells bright blue-green O. cesatiana 



104. Oncobyrsa rivularis (Kuetzing) Meneghini. Monogr. Nostoch. Ital. 96. 



1846. De Toni. Syll. Algar. 5: 114. 1907. 



Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 12. no. SSS- 1899. 



Colony almost spherical, very smooth, opaque, dull brownish-green; 

 tegument almost colorless, soon diffluent; cells 2-6 mic. in diameter, spher- 

 ical or polygonal, arranged in regular radial rows; cell contents blue- 

 green or violet. 



United States. (Collins, Holden and Setchell). 



105. Oncobyrsa cesatiana Rabenhorst. Fl. Eur. Algar. 2: 68. 1865. De 



Toni. Syll. Algar. 5: 116. 1907. 

 Setchell and Gardner. Algae of Northwestern America. Univ. Calif. 

 Pub. Bot. i: 180. 1903. 



