124 
to itis S. Weberi, Kg., with which it agrees in not having the 
fructiferous cells inflated, but from which it differs by the much 
greater diameter of the filaments, greater breadth in relation to 
the length of the cells, and the more compact spiral. 
184. S. longata (Vauch.) Kg. p. 214, Pl. CXXXV.—Low 
ground pool. Orono, Me. Mr. Wilder Colby. 
185. S. dubia, Kg., p. 220, Pl. CXXXV._ Associated with 
the above. Mr. Wilder Colby. 
CuLass II].—CYANOPHYCE. 
Family XVIII.—Nostocacez. 
186. Nostoc rupestre, Kg., p. 283, Pl. CXCVII.—Reported from 
Houlton, Me., but since observed at Bradley, Me. Associated 
with Vaucheria geminata in Chemo stream. Aug., 1890. 
187. Chamesiphon incrustans, Grun., p. 295, Pl. CC,—Our 
specimens young; only 5 x 8 #, and rounded above; attached 
to filamentous alge singly and in clusters. Rather abundant. 
Spring, college meadow. Oct., 1891. 
188. Oscillaria natans, Kg., p. 314, Pl. CCV1.—Filaments 
solitary ; among algz attached to sticks. Pushaw stream. Oct., 
1890. 
189. Oscillaria princeps, Vauch., p. 317, Pl. CCVIL—Our 
specimens bluish green ; cells 5 to 1 in diameter ; end cell round- 
ed; clear and twice as long as the others; filament straight and ’ 
not narrowing toward the end; 30 “ d. Pushaw stream among 
alge. Oct., 1890. 
190, Merismopedia convoluta, Breb., p. 326, Pl. CCX.—Our 
specimens bluish green; colonies 31 s, attached to spruce logs 
floating in the Penobscot. Orono, Me. Oct., 1890. 
EXPLANATION OF PLATE CXXVI. 
Fig. 1. Tetraspora macrospora, geminate spore. 
Figs. 2and 3. Tetraspora macrospora, quaternate spores. 
F igs. 4 and 5. Tetraspora macrospora, large spores with daughter one 
Fig. 6. Tetraspora macrospora, large motile zoospore. 
F igs. 7-9. Apocystis elongata, full grown Thalli, 
Figs. 8-10. Apocystis elongata, younger forms observed. 
Fig. 12, Crater ospermum letevirens; a and 6, spherical zygospores ; % barrel- 
shaped zygospores ; d, abnormal conjugation. 
