138 
6. Gloeothece, Naeg.—G/. magna, n. sp. Thallus large, thin, 
irregularly oblong, pale yellowish green. Cellules nearly twice as 
long as wide, many in a family ; teguments usually colorless at the 
margins, cytioplasm homogeneous. Cellul. .coo12’—.00016” wide. 
Teg. .002”-.006” long. about one-third as wide. Forms a coating on 
small water plants, or floats in ponds, many families joined together. 
7. Vibrio, Muller.—V. Rugulo, Miil—V. lineola, Mil. On 
Nuphar advena, in ponds. 
8. Oscillaria, Bosc.—O. tenerrima, Ktz.—O. major, Vauch.—O. 
Bonnemaisonii, Crouan.—O. brevis, Ktz.—O. gracillima, Ktz. 
g. Phormidium, Ktz.—Ph. congestum, Rabenh.—Ph. vulgare, . 
Ktz. Both on damp earth. 
1o. Microcoleus, Desmaz.—M. terrestris, Desmaz, (Chthono- 
blastus Vaucherta, Ktz.) 
11. Hydrocoleum, Ktz.—H. versicolor, Rabenh. Wet rocks. 
12. Symploca, Ktz.—S. lucifuga, Breb. Shaded clay banks. 
13. Gloeotrichia, J. Ag—Gl. natans, Thuret. Fronds, attached 
to water plants in pools, Buffalo, N. Y.—Gl. pisum, Thuret. On 
‘leaves of a small form of Potamogeton in ponds. 
Dr. Wood evidently found forms of this genus ; the one in a de- 
cayed condition, and the other in an immature state. The one he 
named, G/. incrustata, and the other, Dasyactis mollis. 
14. Zonotrichia, J. Ag.,(Rivularia, Thuret).—Z. paradoxa, n. sp. 
—Thallus hemispherical, gelatinous, bright aeruginous green; trich- 
oma green, or tinged with brown, granular, apex colorless, continuous 
or indistinctly divided; articles subequal -to three times as long as 
wide, very variable ; younger filaments flagelliform, older ones often 
contracted in the middle, or narrow below and gradually widened 
more than half the length, then tapering to a fine point. Filaments 
of the latter form are usually much longer, double the length of the 
former. Diameter of wider parts, .00025’~.0003”. Heterocyst, 
.0004”~.0005".—Z. chrysocoma, Rabenh. Moist rocks, Niagara. 
Wood's Z. parcezonata is probably the young growth of the latter. 
15. Mastigonema, Schwabe., (Ca/othrix, Ag.)—M. caespitosum, 
Ktz. Common on submerged stones.—M. Orsinianum, Ktz. On 
rocks in rapids of Niagara river.—M. plana, Rabenh. Wet rocks, 
Portage, N. Y. 
M. violacea, n. sp. Caespitose, parasitic, aeruginous, trichoma 
simple, occasionally interrupted, usually ending in an extended, 
colorless point. Divisions often indistinct, short, one-forth to one- 
half as long as wide below, and longer towards the ends, finally four 
‘to six times as long as wide. Sheath ample, often truncate, almost 
colorless. Heterocysts more or less compressed. Filaments usually 
‘In clusters, ten to twelve arising from the same thallus, a sort of 
‘warty excrescence. Color of the young plants aeruginous; as they 
mature they change to a purplish iron or amethyst color. Old plants 
are olivaceous-brown. Trichoma .0003”~.00038”. Sheath .00067”— 
.00075". Parasitic on Plectonema in shallow river waters. Near 
Lyngbhya confervicola, Dillw., but beside not being marine, it varies 
in size, and has the divisions twice as large. : 
M. fusca,n. sp. Parasitic on Cladophora, etc. Trichoma sim- 
