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



Forma SENEGALENSE (Nordst.) Hirn, 1900, p. 261, PI. XLV, 

 fig. 277 ; P. B.-A., No. 73. Oogonia and oospores somewhat 

 smaller than in the type, dwarf males shorter ; oogonia to 5- 

 seriate ; vegetative cells with the three median swellings repand, 

 the terminal swellings entire. 



veg. cell, 15-22 M diatu., 3-5 diaui. long, 



oog., 42-52 M " 44-63 M long, 



oos., 3 7-44 M " 36-44 M " 



andr. cell, 15-19 M " 9-18 M " 



nan. cell, 6-8 M " 37-44 /j. " 

 ]\Iass. Africa. 



The description and the measurements just given are founded 

 on the specimens distributed in P. B.-A., No. 73; the original 

 forma scnegalense from Africa, has oogonia not over 3-seriate, and 

 swellings of the vegetative cells entire. As with Oc. cyathi- 

 gcruin, so in this species the antheridia appear to be unicellular 

 unless good material is carefully examined. The peculiar form 

 of the vegetative cells easily distinguishes it from all our other 

 species, Oc. nodulosnm being the only other with similar con- 

 strictions, but there is no danger of confounding the two, if the 

 constrictions are counted ; these two are our only species which 

 are recognizable even when sterile. 



NANNANDRES UNICELLULARES ; OPERCULATA, GLOBOSPORA. 



65. OE. ROTHII (LeCl.) Pringsheim, 1858, p. 69, PI. V, fig. 

 4 ; Him, 1900, p. 265, PI. XL/V 7 , fig. 282 ; P. B.-A., No. 520. 

 Dioecious, nannandrous, gynandrosporous ; oogonia single or 

 2-3-seriate, subdepressed-globose, operculate, division median, 

 narrow ; oospore depressed-globose, almost filling the oogonium, 

 membrane smooth ; suffultory cell not swollen ; androsporangia 

 i-4-celled, s'ubhypogynous, hypogynous, subepigynous or scat- 

 tered ; dwarf males oboviform, unicellular, on the oogonium. 



veg. cell, 6-io/xdiaui., 3-8 diam. long, 



oog., 20-27 fj. " 16-27 M l n g- 



OOS., 17-25 fJ. " 14-20 fJL " 



andr. cell, 6-8 M " 5-10/1 " 



nan. cell, 4 /u, " 11-12 M " 



Mass. /-'./trope. 



66. OE. DECIPIENS Wittrock, 1874, p. 18 ; Wolle, 1887, p. 

 75, PI. LXXVII, figs. 5 and 6; Hirn, 1900, p, 266, PL XLVI, 

 fig. 283; Wittr. and Nordst., Alg. Exsicc., No. 602, in part. 

 Dioecious, nannandrous, gynandrosporous ; oogonia single, or 



