THE GREEN ALGAE OF NORTH AMERICA 63 



veg. cell, female', 23-27 /u diam., 3-4-5 diam. long, 



veg. cell, male, 23-25 M " 2-3 " 



oog., 43-49 /* " 4 6 -57 M long. 



oos., 41-47 fi " 42-49 M " 



anth. cell," 22-24 M " 5-? /* " 



Eastham, Mass., F. S. Collins. Europe. 



The male plants of the typical form of Oe. plagiostomum were 

 observed for the first time in this material, and the dimensions 

 are taken therefrom. The other dimensions are copied from 

 Hirn ; the Eastham material showed slightly larger. 



Page 237, after description of OE. PALUDOSUM var. AMERI- 

 CANUM, insert, 



Var. PARVISPORUM Hirn, 1900, p. 120, PI. XIII, fig. 70. 

 Oospore smaller, not filling the oogonium, oogonium subellip- 

 soid or suboblong-ellipsoid, antheridium subepigynous. sub- 

 hypogynous or scattered. 



veg. cell, 15-20 M diam., 3-6 diam. long, 



oog.,' 38-44 M " 70-86 M long. 



COS., 35-41 M " 54-60 A* " 



anth. cell, 15-17 /* " 7-12 M " 



111., Transeau. Europe. 



Page 239, after description of OE. CRENULATUM forma CYLIN- 

 DRICUM, insert, 



Var. LONGIARTICULATUM Hansgirg ex Hirn, 1900, p. 130, 

 PI. XV, fig. 86. Vegetative cells more slender, oogonia sub- 

 oblong-oboviform, single, oospore oboviform or nearly ellipsoid, 

 not quite filling the oogonium, lines on the membrane distinctly 

 crenate. 



veg. cell, 12-15 M diam., 5-6 diam, long, 



oog., 27-30 M " 57-60/1 long. 



oos., 24-47 /u " 45-48 M " 



Eastham, Mass., F. S. Collins. Europe. 



Page 243, after note on OE. GRANDE var. AEQUATORIALE 

 f. HORTENSE, add, 



Forma ROBUSTUM Hirn, 1900, p. 144. 



veg. cell, female, 34-45 M diam., 2.5-6 diam. long. 



veg. cell, male, 33-42 M " 2.5-6 " " 



oog., 54-66 n. 78-90 /x long. 



anth. cell, 30-36 M " 9- J 5 M ' 



Middlesex Fells, Mass., A. B. Seymour; 111., Transeau. 



