250 OSCILLATOREJ5. 



7. OSCILLATORIA PULCHELLA Hass. 



Plate LXX. Fig. 5. 



Char. Filaments thick, straight, brittle, vivid green. Striae 

 close, very conspicuous. 



Hob. Bottom of pools near Stocket, Aberdeen : Dr. 

 Dickie. Cheshunt: A.H.H. 



The filaments of this fine species are more robust than those 

 of O. virescens and the striae closer. The only other described 

 species with which it could be confounded is O. spadicea, 

 which it resembles in the closeness and strength of the striae ; 

 but the filaments in O. pulchella are rather finer and much 

 more brittle. 



8. OSCILLATORIA VIRESCENS Hass. 



Plate LXXI. Fig. 9. 



Char. Stratum terrestrial, of a light aruginous green colour. 

 Filaments of considerable diameter, pale yellowish green 

 straight, brittle. Stria? subdistant. 



Hob. Cheshunt, Herts : A. H. H. Between River Head 

 and Chipstead, bankside : Mr. Jenner. 



This would appear to be a distinct as well as a fine species. 

 The filaments are longer than those of O. tennis, and more- 

 over preserve their diameter in drying. Striae nearly a dia- 

 meter of the filaments apart, conspicuous. 



9. OSCILLATORIA THERMALIS Hass. 

 Plate LXXII. Fig. 3. 



Char. Filaments small, green. Stria3 straight, brittle, sub- 

 distant, very evident. 



Hab. In a stream of hot water, Stevenston : Rev. D. 

 Landsborough. 



The filaments of this species are as slender as those of O. 



