NOSTOCE.E. 245 



Plate XCV. fig. 3. a, portion of triohome, with heterocysts X 400 ; 

 b, portion X 600 ; c, fertile portion, with spores X 600 ; d, spores X GOO ; 



e, spore germinating, after Thuret. 



Nodulazia Harveyana. Thur. in Ann. Sd. Nat 1875, 378. 



Trichomes much curved, composed of cells nearly as long as 

 broad. Heterocysts subquadrate, rather longer than wide, and 

 of the same width as the joints. Spores spherical, almost 

 twice the diameter of the joints. 



SIZE. Trichomes -0065 mm. diam. 



Born, and Thur. Notes Alg. ii., t. 29, f. 14-16. 



Spermosira Harveyana, Thw. in Harv. Phyc. Britt. t. 173, 



f. c. Eabh. Alg. Eur. ii., 295. 



In brackish ditches. 



Plate XCV. Jig. 4. , portion of trichorne with heterocysts X 400 ; b, 

 the same X 600 ; c, portion of trichome with spores X 600 ; d, germi- 

 nating spoi'es, after Thuret. 



FAMILY II. LTNGBY^J. 



Filaments without heterocysts, and destitute of a terminal 

 hyaline hair, single, and scattered, or numbers associated in 

 bundles and enclosed in a common sheath, often radiating. 

 Joints shortly cylindrical, disc -shaped in section. 



GENUS 100. SFZRULINA. Link. (1834.) 



Trichomes articulated, spirally twisted, motile, nestling in a 

 more or less liquid colourless matrical mucilage. Propagation 

 unknown. 



Consult Cohn in Nova Acta Car. Leop. vol. xxiii. Braun in Botauische 

 Zeitung 1852, p. 395. Keinicke Beitr. zur neuern Mikrosk ii., pp. 

 1-56. 



Spirulina Jenneri. Kutz. Tab. Phyc. i., t. 37, J. 11. 



Trichomes more or less elongated, distinctly articulated, 

 spirals lax, distant, joints equal in length to their diameter, or 

 a little shorter. Cell-contents pale or bright blue green. 



SIZE. Trichomes -OOT-'OOS mm. diam. 



Rabh. Alg. Eur. i., 90. Kirch. Alg. Schl. 250. 



Spirillum Jenneri, Hass. Alg. 277, t. 75, f. 5. 



Arthrospira Jenneri, Hedwigia i., p. 32, t. 5. 



In stagnant water. 



Plate XCV1. fig. 1. Portions of trichomes X 400, 



