JI9G NEMATOPHYCE.E. 



Reproduction takes place by means of asexual zoogonidia, and sexu- 

 ally produced oospores. The latter do not at once produce new plants, 

 but several zoospores. The zoospores, which are developed in the early 

 part of the year from resting- spores of the previous year, produce only 

 asexual plants which only form zoogonidia. After a series of asexual 

 generations, of variable length, a sexual generation arises, which accord- 

 ing to the species is monoecious or dioecious. Fertilization produces 

 one oospore in the oogonium, which developes into a reproductive body, 

 from the cells of which zoospores proceed in the next period of vegeta- 

 tion. Zoogonidia may originate in all the vegetative cells of the Coleo- 

 cha3tea3, and are always formed from the entire contents of the mother- 

 cell, escaping through a round hole in the cell wall. 



<; Iii C. piih-htatd the terminal cell of a branch swells up, and at the 

 same time elongates into a narrow sac, which then opens, and exudes a 

 colourless mucilage. The protoplasm of the swollen part, which con- 

 tains chlorophyll, forms the oospore, in which a nucleus is visible. The 

 antheridia are formed at the same time in adjoining cells, two or three 

 protuberances growing out, which become separated by septa ; each of 

 the cells thus formed, which have somewhat the shape of a flask, is an 

 antheridinm ; its entire contents form an antherozoid of oval shape 

 with 2 cilia, which is endowed with motion like a zoogonidium; its 

 entrance into the oogonium has not yet been observed. The effect of a 

 fertilization is seen in that the contents of the carpogonium become 

 surrounded with a proper membrane and form the oospore." 



Coleochsste soluta. Prings. JaUrb. t. I,/. 2. 



Threads radiating from a common centre, furcately branched, 

 of equal length, closely packed side by side, prostrate, but not 

 connate, forming ar n-bicular disc. Cells one and a-half to 

 three times as -long as broad, oogonia placed before the terminal 

 cells, glo^se, corticate. 



SIT-. Cells -025 mrn. 



tf abh. Alg. Eur. in., 389. Kirch. Alg. Scliles. p. 50. 



Attached to aquatic plants. 



Plate LXXriII. Jig. 3. Plant of Coleoclicete soluta X 400. , Oogo- 

 nium X 250 diam. 



Coleocliaete scntata. Brcb. Ann. SGI. Nat., 1844, p. 29, t. 2. 



Filaments and their branches radiating from the centre, very 

 densely connate in one stratum, forming a kind of parencby- 

 matous orbicular disc ; cells quadrangular, nearly equal or twice 

 as long, oogonia subglobose, peripherical, corticate above, naked 

 below. 



SIZE. Cells -02--022 mm. 



Rabh. Alg. Eur. iii., 390. Hass. Alg. 217, t. 77, f. 6. 

 Prings. Jahrb. t. i., f. 4 ; t iii., f. 3, 4. 



Phyllactidium setigemm, Kutz. Tab. Phyc. iv. 



On aquatic plants. 



Plate LXXIX. Coleoclicete scntata. a, plant X 200. b, portion with 

 oogonia. c, portion with antheridia cells, d, zoospore, active and at 

 rest, e, development of young plants. 



