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



celled, subepigynous or more rarely subh) T pogynous ; sperniato- 

 zoids binate, division horizontal. 



veg. cell, 12-15 i" diam., . 2 /4~5 diaui. long. 



oog., 40-43 M " 3 8 -44 M long. 



oos., 33-35 M " 33-35 /x " 



anth. cell, 11-14 M 10-15 n " 



Mass. Europe. 



Resembles Oc. crispum, but the oospores are smaller in pro- 

 portion to the oogonia, and the oogonia are always solitary ; 

 from Oc. autumnalc it is distinguished by the smaller but longer 

 vegetative cells. 



37. OE. AUTUMNALE Wittrock, 1874, p. ii ; Wolle, 1887, p. 

 73, PI. LXXXI, figs. 1-5; Him, 1900, p. 167, PI. XXVI, fig. 

 151. Monoecious ; oogonia single, oboviform-globose, opercu- 

 late, division superior ; oospore globose or subglobose, filling or 

 nearly filling the oogoniurn, membrane smooth ; antheridia 1-2- 

 celled, subepigynous, hypogynous or scattered ; spermatozoids 

 binate, division horizontal ; basal cell elongate, terminal cell 

 shortly acute. 



veg. cell, 16-20 fj. diam., 1/4-2 Y Z diam. long. 



oog., 39-45 /x " 45-51 M long. 



oos., 37-42 M " 37-44 M " 



anth. cell, 15-18 y. " 9-10 fj. " 



Pa. Europe. 



Not far from Oc. crisp u in, but with stouter and shorter vege- 

 tative cells, and relatively less swollen oogonia. Its occurrence 

 in America has no other proof than the reference in Wolle. 



38. OE. PRINGSHEIMII Cramer, 1859, p. 17, PL I, figs. 1-4; 

 Wolle, 1887, p. 90, PI. LXXXII, figs. 4-6; Him, 1900, p. 170, 

 PI. XXVII, fig. 155; Rabenhorst, Algen, No. 790. Dioe- 

 cious ; oogonia 2-6-seriate or single, suboboviform-globose, 

 operculate, division superior ; oospore globose, almost filling 

 the oogonium, membrane smooth, thickish ; male plant slightly 

 more slender than the female ; antheridia to lo-celled, always 

 alternating with vegetative cells ; spermatozoids binate, divi- 

 sion horizontal ; basal cell elongate, terminal cell obtuse or 

 short-apiculate. 



veg. cell, female, 14-20 /j. diam., 2-5 diam. long, 



veg. cell, male, 12-16 /u " 2-4 " ." 



oog., 35-43 fj. " 36-46 M long, 



oos., 3-37 /" " 3-37 M " 



anth. cell, 11-15 /* " 6-9 M " 



N. Y., Pa., Florida. Europe, Africa, Australia. 



