266 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



Somewhat resembling Oe. pyri forme, but a smaller plant, and 

 with peculiar basal and terminal cells. 



73. OE. CATARACTUM Wolle, 1887, p. 77, PI. L,XXXV, 



figs. 10-12 ; Hirn, 1900, p. 308, PI. XI^II, fig. 264. Dioecious, 

 nannandrous, idioandrosporous ; oogonia single or 2, often ter- 

 minal, oboviform-globose, subglobose or broadly ovate, pore 

 superior ; oospore globose or oboviform-globose, almost filling 

 the oogonium ; androsporangia 2-6-celled, dwarf males much 

 curved., on suffultory cell or sometimes on the cell below this ; 

 antheridium interior ? 



veg. cell, 28-38 /u diatn., J^-3 diatu. long. 



oog., 55-6 /* " 60-75 M long. 



oos., 50-55 M " 50-60 M " 



andr. cell, 26-30 M " 10-15 M " 



nan. cell, 10 M " 65 /* " 



Pa. 



Although this description appears to be fairly complete, the 

 species is placed by Hirn among those insufficiently known, as 

 Wolle's statements in regard to the male plant are contradictory ; 

 this being given as unicellular and also as having internal an- 



theridia. Hirn suggests that it may be a form of Oe. crassius- 

 culum. 



74. OE. LONDINENSE Wittrock, 1874, p. 39; Wolle, 1887, 

 p. 94, PI. L,XXV, figs. 7 and 8 ; Hirn, 1900, p. 317. Oogonia 

 2 or i, globose, division median, oospore globose, almost filling 

 the oogonium ; antheridia (or androsporangia ?) i-2-celled, hy- 

 pogynous. 



veg. cell, 10-15 M diani., !/^-5 diarn. long, 



oog., 33-35 M " 33-43 M long. 



OOS., 27-32 H " 27-32 M " 



anth. cell? 12 /u. " 10-11 M " 



N. J., according to Wolle. A very imperfectly known species, 

 and American only with some doubt, there being no other record 

 than Wolle's. 



2. BULBOCHAETE Agardh, 1817, p. XXIX. 



Filaments branching ; vegetative cells increasing in size to 

 upper end ; basal cell often lobed, attached to substratum ; ter- 

 minal cell of each filament and branch produced into a long, 

 hyaline seta with a bulbous base ; plant increasing mostly by 

 division of the basal cell of the principal filament or of a branch ; 

 oogonia arising by a double division of a vegetative cell. 



