278 NOSTOCHINE^E. 



" It spreads over the dry naked earth. Stratum several 

 feet in extent, firm, coriaceous, of a glossy black colour, void 

 of lubricity. Filaments about half a line in length, twisted 

 like a corkscrew, radiating in all directions." Carm. 



When dried, the filaments lose their regularly spiral 

 character. 



3. SPIRILLUM MINUTISSIMUM Hass. 



Plate LXXV. Fig. 8. 



Char. Filaments excessively small, describing usually about 



three turns.' 

 Hab. Ireland : Mr. Moore. 



This exceedingly minute species I received from Mr. Moore. 

 The spiral character of the filaments is retained in drying, 

 which is not the case in the previous species. I was much sur- 

 prised to notice, when examining a portion of a specimen 

 which had been preserved for a considerable time, that the 

 filaments were in lively movement, turning round and round 

 repeatedly, and with exceeding rapidity. 



4. SPIRILLUM THOMPSON i Hass. 



Plate LXXV. Fig. 7. 



Char. Threads rather large, moniliform. Globules of equal 

 size throughout their entire length. 



Anabaina ? spiralis Thompson, Annals of Nat. Hist. vol. v. 

 Hab. Ballydrain Lake, near Belfast : Mr. Thompson. 



" The specimens obtained were invariably of similar 

 breadth, and rarely presented more than four spiral turns, and 

 when of this size were one fiftieth of an inch in length. The 

 species at first, when mingling with the water, is of a dark 

 green colour ; when in calm weather it ascends to the surface 

 in separate particles, it appears pale green ; when it does so 

 en masse (the earliest symptom of decay), it is of a pale blue ; 

 and in the last stage of decomposition, ferruginous. Having 

 on the 27th September brought home in several phials spe- 



