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



4. C. SCUTATA Brebisson, 1844, p. 29, PI. II, figs. 1-7; Rab- 

 enhorst, Algen, No. 1126 ; Wolle, 1887, p. 64, PI. L/KXII, figs. 8- 

 13. Dioecious; frond orbicular, subparenchymatous, monostro- 

 matic, composed of laterally united, branching filaments, radiat- 

 ing from a center; cells quadrangular, 25-45 P diam., 1-3 diam. 

 long; oogonia subglobose, naked below, corticated above, 140- 

 160X120 //.; antheridia produced 4 from the division of a vege- 

 tative cell. Mass., N. Y., N. J., Neb., Colo. 



Europe, Asia, So. America, New Zealand. 



Distinguished from all but C. orbiculan's by the continuous, 

 monostromatic frond. 



5. C. ORBICULARIS Pringsheim, 1860, p. n, PL I, fig. 5 ; PL 

 III, figs. 6 and 7 ; PL VI, figs, i and 2 ; Wolle, 1887, p. 64, 

 PL LXXII, fig. 14. Frond orbicular, parenchymatous, mono- 

 stromatic, composed of laterally united, branching filaments; 

 cells oblong, quadrangular or polygonal, 8-i6/xdiam., about 2 

 diam. long; oogonia ovoid, 60-85X50-65 p., naked below, more 

 or less corticated above ; antheridia not known. Mass., N. J., 

 Neb. Europe, New Zealand, Hawaii, 



Closely resembling C. scutata, but more regular in outline, 

 and with smaller cells ; if antheridia should be found similar to 

 those of C. scutata, it might be treated as a variety of the latter. 



6. C. PULVitfATA A. Braun in Kiitzing, 1849, p. 425; 1855, 

 PL LXXXIX, fig. 3; Wolle, 1887, p. 64; P. B.-A., No. 75. 

 Monoecious ; frond pulvinate, gelatinous, composed of branch- 

 ing filaments, radiating from a common center ; cells 20-40 /u. 

 diam., 1^-2 diam. long; oogonia at. first lageniform, globose 

 when mature, corticated, about 150/4 diam., including cortex; 

 oospore iio/x diam.; antheridia flask-shaped, sessile, near the 

 oogonia, 17 /* diam., 2*4 diam. long. Mass., Pa., Alaska. 



Europe. 



Easily distinguished from other species by the cushion-like, 

 not disk-shaped frond, formed of regularly radiating filaments. 



7. C. DIVERGENS Pringsheim, 1860, p. 5, PL I, fig. i ; PL 

 II, fig. 2. Monoecious ; frond pulvinate, gelatinous, composed 

 of branching filaments, with no definite center ; cells about 25 /M 

 diam., 1-3 diam. long ; oogonia including cortex up to 135 p. 

 diam. ; oospore to 95 /x. Fig. no. These dimensions are for 

 the type, which has not yet been noted in America ; we have 



Var. MINOR Hansgirg, 1886, p. 39 ; P. B.-A., No. 1331. Cells 

 i2-i8/i diam., 1-2^ diam. long; oogonia 60-80 p., oospore 50- 

 70 fj.. On Batrachospermum and other algae. N. H. Europe. 



