64 TUFTS COLLEGE STUDIES, VOL. IV, No. 7 



According to Transeau this form is distinct and well marked 

 in Illinois, and seems to deserve varietal rank. 

 Page 245, after OE. CRISPUM, add, 



Forma INFLATUM Him, 1900, p. 161, PI. XXV, fig. 140; 

 Transeau, 1917, p. 231. A slender form, with larger oogonia 

 and oospores. 



veg. cell, 12-16 n diam., 3-6 diam. long. 



oog., 40-50 M " 48-53 M 



oos., 37-45 M " 38-45 M 



anth. cell, 8-12 M " 9-12 M " 



Mich., Transeau. l-.nrope. 



Page 260, after the description of OE. CYATHIGERUM, add, 



The typical form has been found in Ohio, Transeau. 



Var. ELLIPTICUM Magnus & Wille ex Him, 1900, p. 255, 

 PI. XLIV, fig. 271. 



Vegetative cells shorter, oogonium and oospore smaller ; 

 oospore often not quite filling the oogonium, of varying form, 

 quadrangular-ellipsoid or .nearly ellipsoid, rarely subglobose ; 

 oogonium single or 2 ; dwarf males on suffultory cell, more 

 rarely on oogonium. 



Page 262, after OE. UNDULATUM forma SENEGALENSK add, 

 Var. AMERICANUM Transeau, 1917, p. 232. Vegetative cells 



as in the typical form, oogonia and oospores larger. 

 oog., 58-68 M diam., 60-80 M long. 



oos., 48-60 M " 48-56 M " 



Trout Lake, Mich., Transeau. 

 Forma SENBGALBNSB, the only certainly American form be- 



fore recorded, is about as much smaller than the typical form 



in these dimensions as var. AMERICANUM is larger, but differs 



in other respects. 



Page 266, after description of OB. LONDINBNSB, add, 



75. OB. INTERMEDIUM Wittrock ex Him, 1900, p. 94, PI. V, 



