136 



XVXicKOSpora fioccosa. (Ag.) Thuret. RecJi. t. 17, /. 4-7. 



Articulations before division about twice as long as the 

 diameter, after division about equal, or a little shorter, slightly 

 constricted at the joints. 



SIZE. Threads -015--017 mm. diarn. (according to Kirschner 

 0075 --01 mm. diam.). 



Eabh. Alg. Eur. iii., 321. Thuret. Ann. Sci. Nat. 1850, t. 

 17, f. 4-5. 



Conferva floccosa, Ag. Syst. p. 89. Kutz. Tab. iii., t. 43. f. 

 3. Eng. Fl. v., 351. Eng. Bot. ii., t. 2474. Harv. Man. 126. 

 Mack. Hib. 224. Gray AIT. i., 310. Kirsch. Alg. Schl. p. 79. 



Lyngbya floccosa, Hass. Alg. 223, t. 60, f. 1-2. Jenner, Tunb. 

 Wells, 188. 



Conferva fug acissima. Dill. Conf. Supp. t. B. 



In stagnant water. 



Plate LI II. Jiff. 3. a, I, portions of threads X 300 ; c, cells divided 

 across for the escape of zoogonidia X 300 ; d, zoogonidia. 



GENUS 59. CONFERVA. (Linn.} Link. (1820.) 



Articulate threads simple, articulations cylindrical. Chloro- 

 phyllose mass homogeneous or granulate, including starch 

 granules. 



Vegetation by division in one direction. 



Propagation unknown, (? by resting-spores which subse- 

 quently produce zoogonidia). 



Kecently "Wille has declared his belief in the universality of resting- 

 spores in the whole genus Conferva,* although it is hardly clear what 

 is his conception of the limits of the genus. In a new species which he 

 has described under the name of Conferva WittrocJcii, he gives detailed 

 account of spore formation, which it is presumed may be accepted as a 

 type of what usually takes place. 



" The chlorophyllaceous contents contract, and become rounded. The 

 colouring matter collects principally in the ends of the cells, so that the 

 substance in the middle appears almost colourless; but after the con- 

 traction of the cell contents the chlorophyllaceous portions of the 

 protoplasm draw nearer together, until at last they coalesce and form a 

 round or elliptical body within the mother cell ; they then begin to 

 surround themselves with a membrane, which later consists of two 

 distinct layers. The spores are generally set free by the filaments 

 resolving themselves into H shaped cells (in which the cell wall of each 

 cell has a transverse fissure in the middle of the transverse walls) ; the 

 spores then fall out. Sometimes they escape by the cell walls becoming 

 converted into mucilage, their layers becoming gradually indistinguish- 

 able. On first germinating, the size of the spores increases, as the 

 result of which the outer membrane bursts. The outer membrane 

 consists of two pieces with pointed ends, one being much larger than the 



* Ofversigt af Kon. Vetensk Akad Porhandl. xxxviii (1881). " Journal of Eoyal 

 Microscopical Society," Dec., 1882, p. 836. 



