148 WISCONSIN PHYTOPLANKTON 



Lemmermannia tetrapedia (Kirchner) Lemmermann, Arkiv. for Botanik 2, 

 No. 2: 157. 1904. 



Coenobia four-celled, with, a very small rectangular open space at 

 the center. Frequently joined in multiple coenobia of sixteen cells that 

 may be connected in turn to other 16-celled multiple coenobia. Cells 

 flattened, triangular, with rounded corners. Cell contents homogeneous, 

 or with a single parietal chloroplast, with or without pyrenoids. (Fac- 

 ultative Planktont). 



Diam. cells 4.8-9.5 p.; diam. coenobia 8-15 p.; diam. 16-celled multiple 

 coenobia up to 40 /*. 



Palmer (rr). 



Certain investigators have noted that the cell contents are at times 

 absolutely homogeneous. This has caused Schroder to consider the alga 

 a species of Tetrapedia, one of the Myxophyceae, but the Wests have 

 given cogent reasons for considering it a Crucigenia. I have found a 

 distinct parietal chloroplast and pyrenoid in the cells whereas Chodat 

 states that there is a chloroplast but no pyrenoid. His founding of the 

 genus Lemmermannia upon this single character (lack of a pyrenoid) 

 has rightly been called by G. S. West (Brit. Freshw. Algae 217. 1904) 

 "the climax of absurdity." 



CRUCIGENIA FENESTRATA Schmidle. PI. 37, Fig. 3. 



Allg. Bot. Zeitsckr. 6: 234. 1900. 



Staurogenia fenestrata Schmidle, Allg. Bot. Zeitschr. 3: 107, fig. 1. 1897. 



Coenobia four-celled, rectangular, with a medium-sized opening at 

 the center; with an inconspicuous gelatinous sheath. Frequently in 

 multiple coenobia with the component coenobia lying close together. 

 Cells trapezoidal, with the longest face at the outside of the coenobe. 

 Chloroplast single, except just before division, parietal, without a pyre- 

 noid (?). (Euplanktont). 



Cells 3-5 ju, broad, 5-12 /* long ; coenobia 8-14 /* broad. 



Bettin'e (rr), White Sand (rr). 



The specimens that I have found do not agree in all respects with 

 Schmidle 's description since there was no gelatinous sheath surround- 

 ing the coenobe and filling the central space. 



CRUCIGENIA LAUTERBORNEI Schmidle. PI. 37, Fig. 4. 



Allg. Bot. Zeitschr. 6: 234. 1900. 



Staurogenia Lauterbornei Schmidle, Allg. Bot. Zeitschr. 2: 192, fig. 1. 1896. 



Coenobia four-celled, cells in contact with one another at their apices 

 only and with a large square open space at the center of the coenobe. 



