90 Rhodora [May 
Anabaena sphaerica, Bornet & Flahault. On leaves of Nymphaea 
advena in lake off Shawanaga River, Aug. 27. This species has not 
been previously recorded from Canada, or from the Eastern or Middle 
States. 
Cylindrospermum minutum, Wood. Marsh, Killarney, Sept. 4. 
This is the first Canadian record for this species. 
Cylindrospermum muscicola, Kuetzing. On leaves of Nymphaea 
advena in a lake off the Shawanaga River, Aug. 27. Not previously 
recorded from Canada. 
Seytonema myochrous, Agardh. On gneiss rocks at water’s edge on 
Station Island, Go-Home Bay, Aug. 17. In pool in flat limestone - 
rock on the shore at Tobermory, Sept. 9. 
Tolypothrix tenuis, Kuetzing. On dead twigs in lake off the Shaw- 
anaga River, Aug. 27. Floating at the shore of Georgian Bay, 
Waubaushene, Aug. 24. 
` Tolypothrix penicillata, Thuret. Forming a coating of little dark 
brown tufts on gneiss rocks at the water’s edge on Station Island, Go- 
Home Bay, Aug. 19. Occurring as little brownish-black tufts on 
limestone rocks just beneath the water near Rattlesnake Harbour, 
Fitzwilliam Island, Sept. 8. Not before recorded from Canada. 
Tolypothrix distorta, Kuetzing. Forming a close brownish hairy 
coating on gneiss rocks at the water’s edge on an island near Collin?s 
Inlet, Algoma District, Sept. 3. This is the first Canadian record. 
Calothrix adscendens, Bornet & Flahault. On dead shells of Unio 
complanatus in Georgian Bay at Waubaushene, Aug. 21. Not pre- 
viously recorded from Canada. 
Calothrix parictina, Thuret. On limestone rocks in Georgian Bay 
near Rattlesnake Harbour, Sept. 8. 
Rivularia laurentiana, sp. nov. Coloniis ad 5 mm. diam., glo- 
bosis, subviridibus, pleurumque solitariis, solidis, firmis sed non calce 
incrustatis. Filamentis ad 750 u longis, 5-8 u diam., densis. Tricho- 
matibus 4-7 u diam., sensim in setas achroas attenuatis. Vaginis 
spissis et aequis, 1 u. crassis. Cellulis 2-10 u longis. Heterocystis 
10-12 u diam., globosis aut ovatis minore extremitate deorsum versa. 
Gonidiis semper absentibus. 
Colonies up to 5 mm. in diameter, spherical, light green, usually 
solitary, solid, firm but not incrusted with calcium carbonate. Fila- 
ments up to 750 y in length, 5-8 y in diameter, crowded. Trichomes 
4-7 u in diameter, tapering to a colorless hair. Sheaths close and 
even, 1 y thick. Cells 2-10 u in length. Heterocysts 10-12 y in diame- 
ter, spherical or ovoid with the small end downwards. Gonidia never 
present. 
