THE GREEN ALGAE OF NORTH AMERICA 265 



Wolle says frequent, but gives no definite locality. The con- 

 siderable variation both in length and diameter of cells in the 

 same plant, is quite noticeable. 



SPKCIES OF WHICH THK ORGANS OF FRUCTIFICATION ARE 

 PARTLY KNOWN. 



70. OB. GIGANTEUM Kiitzillg, 1845, p. 2OO ; Wolle, 1887, p. 



94, PI. LXXVI, figs. 1-6 ; Him, 1900, p. 295, PI. XXIII, fig. , 

 115; Phyk. Univ., No. 177. Oogonia single, slightly swollen, 

 cylindric-oboviform, pore superior; oospore cylindric-ellipsoid 

 or subellipsoid, nearly filling the oogonium, membrane appar- 

 ently triple; outer membrane smooth, median with 25-30 longi- 

 tudinal series of pits ; inner membrane smooth ; suffultory cell 

 often larger than the other vegetative cells, but not swollen. 



veg. cell, 30-50 fj. diam., 2-4/4 diam. long. 



suf. cell, 40-60 M " i)4-3/4 " " 



oog., 53-69 M " 67-106 n long. 



oos., 51-65 M " 65-103/4 " 



Mentioned by Wolle, but without exact locality ; we have no 

 other species with similar markings to the spore. 



71. OE. PYRIFORME Wittrock, 1874, p. 39; Wolle, 1887, p. 



95, PI. LXXVII, figs. 11-13; Him, 1900, p. 303, PL XXV, 

 fig. 137. Oogonia single, pyrifonn, operculate ; antheridia 2-3- 

 celled, subepigynous, hypogynous or scattered. 



veg. cell, 13-16 /u diani., 3/^-6 diam. long. 



oog., 40-45 M " 54-6o n long. 



Panth. cell, 10-12 M " 9-12/1 " 



N. J. Australia. 



A very imperfectly known species ; but the form of the 

 oogonium is peculiar; pyriform, or perhaps better, "top- 

 shaped." 



72. OE. SANCTI THOMAE Wittrock and Cleve in Wittrock, 

 1874, p. 40 ; Him, 1900, p. 304, PI. XXIX, fig. 173. Oogonia 

 single or 2-3, pyriform, operculate, division superior; oospore 

 pyriform-oboviform, not quite filling the oogonium, membrane 

 smooth ; basal cell subhemispherical, not elongate ; terminal 

 cell very slender, subhyaline. 



veg. cell, 7-15 M diam., 2-6 diam. long. 



term, cell, 2-4 M " 5-7 



oog., 28-33 /J. " 36-50 /t 



oos., 25-30 M " 28-35 M 



basal cell, 14-23 M " 8-12 M 

 St. Thomas, W. I. 



