PRO TOCOCCOIDE& 



417 



It is impossible to distinguish between the genera Protococcus (Ag.), 

 Pleurococcus (Meneg.), and Palmella (Lyngb.) ; but it is doubtful 

 whether Chlamydococcus (A. Br.) and Chlamydomonas (Ehrb.), which 

 undergo much more complicated changes of form, and in some condi- 

 tions very closely resemble Protococcus, have been rightly identified with 

 it (see p. 299). Haematococcus Butschlii (Blockmann, Ber. Heidelberg 

 Naturh. Ver., 1886) probably belongs to Chlamydomonas. Schnetzler 



FIG, 346. Glochiococcns anglicus Benn. 

 ( x 200). (From nature.) 



FIG. 347. Chlorococcum gigas Griin. (x 300). 

 (After Cooke.) 



(Bull. Soc. Vaud. Sc. Nat, 1882, p. 115) regards Palmella uvaeformis 

 (Ktz.) as a stage in the development of a Stigeoclonium ; while Ander- 

 sson identifies it with Draparnaldia. 



Glochiococcus (Lagerh.) (Acanthococcus, Reinsch, Ber. Deutsch. Bot. 

 Ges., 1886, p. 237) differs from Palmella in the cell- wall, which is thick 

 and lamellated, being in most of the species furnished with warts, 

 spines, or other prominences. The cells, which closely resemble the 

 zygosperms of desmids, divide into eight or sixteen daughter-cells, which 

 remain but a short time in connection, being set free by the deliques- 

 cence of the outer membrane. 



Chlorococcum (Fr.) is analogous to Chroococcus among the Chroo- 

 coccacese. Several species are common in pools or on moist walls or 

 rocks. In C. gigas (Griin.) the cells are as much as 

 o'0 1-0-015 mm. in diameter, and either a single cell 

 or a colony of cells is enclosed in a very thick lamel- 

 lated hyaline envelope. In Glaocystis (Nag.), corre- 

 sponding to Gloeocapsa among the Cyanophyceae, 

 the cells are associated in families of two, four, or 

 eight, each family being enclosed in a lamellated gela- 

 tinous envelope, in addition to the similar envelope which encloses each 

 cell. In Schizochlamys (A. Br.) the cells escape from the surrounding 

 envelope by the latter splitting into two or four equal parts. Eremosphcera 

 (de By.) is a beautiful bright green globe, 0-1-0-15 mm - m diameter, 

 floating free in bog-pools, and enclosed in a thin hyaline envelope. 



E E 



FIG. 348. Schizochlamys 

 gelatinosa A. Br. (x 

 600). 



