WEST : NOTES ON THE FRESH-WATER ALGZ. 217 
Anabena oscillarioides Bory. (Born. et Flah., Revis. des 
Nostoc. Heterocyst., quatr. et. dernier fragm., p. 233 ; 4. Ralfsit 
Cooke, Brit. Freshw. Alg., p. 237, tab. 94, fig. 1.) _Newsholme. 
A slightly smaller form. 
Crass. cell. 3°5—-4m; crass. heterocyst. 6—6'5u; long. 
heterocyst. 6°5—7°7; long. spor. 17°3—34'5m; lat. spor. 
9510p. 
ee Pee (L.) Ralfs. forma paullo minor. 
Riccall Com 
Crass. Mika 4p; crass. spor. 5—8p ; long. spor. 30—5op. 
OrpeR SCYTONEMACE2. 
Tolypothrix lanata (Desv.) Wartm. Riccall Common 
rass. fil.=13°5- 16; crass. trichom. 8°6—9° ba: long. 
heterocyst. g—12p; lat. heterocyst. r1°*5—15p. 
Tolypothrix tenuis Kiitz. Riccall Common. 
OrpER OSCILLARIACE#. 
Oscillaria Frolichii Kiitz. Beverley; Routh; Loftsome Bridge 
near Wressle. 
Oscillaria limosa (Roths.) Ag. Waghen. 
Sus-CLass CHROOCOCCACE#, 
OrpER CHROOCOCCACE®. 
Chreococcus turgidus (Kiitz.) Nag. Riccall Common ; Hornsea 
Mer 
: Microcystis protogenita (Bias.) Rabh. Routh. 
_ Clathrocystis zruginosa (Kiitz.) Henfr. Hornsea Mere, 
- Merismopedia glauca (Ehrmb.) Nig. Riccall Common. 
_ Merismopedia punctata Meyen. Riccall Common. | 
oo Joly Hips. = 
: Tetrapedia Reinschiana Arch. Riccall Common. 
y CLASS DIATOMACE#. 
Cyclotetta. operculata (Ag.) Kiitz. Loftsome Bridge near 
Wressle. 
Melosira varians Ag. Resco; ; Newsholme. 
Surirella panduriformis Sm. Tickton. 
Surirella biseriata (Ehrnb.) Bréb. Beverley. 
Surirella —— Kiitz. Near Meaux Abbey. 
