PROTOCOCCOIDEzE 



413 



ovate or pear-shaped. 0-02-0 025 mm. in diameter in the larger species, 

 often apiculate or spinous at the apex. The cell-contents divide, by 

 successive biparcitions. into zoospores, which commence swarming while 

 still within the mother-cell, indicating an approach 

 to Hydrodictyon. They escape through a lateral or 

 terminal fissure. Nearly allied to Characium are 

 Hydrocytium A. Br., also met with in fresh water, 

 and Hxdriamim Rabh., found in similar localities. 

 In the last genus the zoospores also escape at the 

 apex. In Apiocystis Xag. a large number of gonids 

 are sparsely scattered through a stalked pear-shaped 

 gelatinous envelope attached to fresh-water algge. 

 They, occur chiefly in the periphery, and are ulti- 

 mately converted into zoospores. 



Codiolum A. Br. is a club-shaped marine organism, about 0*04 mm. 

 in diameter, and four to six times the length, attached to rocks or sea- 

 weeds. It is propagated by zoospores, or, according to some observers, 

 also by resting hypnospores. Haiickia Bzi. (Xuov. Giorn. Bot. Ital., 



Fig. 340. — Characium 

 ornitJwcephahiJii A. 

 Br. (x 600). (After 

 A. Braun.) 





'^ - 





Fig. 341. — Apiocystis Brartniana Nag. 

 ( X 100). (From nature.) 



Fig. 342. — Codiolum grcgariiim K. Br. (magnified). 

 (After Hauck.) 



1880, p. 290) grows on rocks exposed to the sea. The gonids are placed 

 in pairs on a long hyaline stalk ; it produces zoospores of two different 

 sizes, but no process of conjugation has at present been observed. 



