38 



PROTOZOA 



P. morum Bory. (Fig. 49). Colony up to .09 mm. in diameter: 

 cosmopolitan. 



4. EUDORINA Elirenberg-. Colony more or less spherical, composed 

 usually of 32 (occasionally of IG or 64 cells) which are 



• 1 /,. not close together and do not reach the center, and 



are surrounded by an envelope; asexual reproduction 

 as in Gonium; at certain times sexual colonies appear, 

 the female being like the ordinary colony, the male 

 colony consisting of long, spindle-like cells which be- 

 come free and unite with the female cells forming the 



Fig. 49 



Pandorina morum 

 (Conn). 



zygotes: 2 species. 



Colony about .15 mm. 



E. elegans Ehr. (Fig. 50). 

 in diameter: cosmopolitan. 

 5. Platydorina* Kofoid. Colony flattened, horseshoe-shaped, com- 

 posed of 16 or 32 cells with the flagella on both faces on alternate cells 

 which are alike; asexual reproduction as in Gonium; sexual reproduction 

 not observed : 1 species. 



P. caudata Kofoid (Fig. 51). Colony about .15 mm. long and .13 

 mm. wide ; posterior end of envelope with 3 or 5 tails : Illinois. 



Fig. 50 Fig. 51 



Fig. 50 — Eudorina elegans (Jordan and Kellogg). Fig. Zl—PlaUjdorina caudata 

 (Kofoid). Fig. 52— P/codor/na ilUnoisensis (Kofoid). 



6. Pleodorina Shaw. Colony more or less spherical, composed of 

 16 to 128 cells, certain of which are reproductive and the rest vegeta- 

 tive, the former being twice the size of the latter, and posterior in 

 IDosition; asexual reproduction as in Gonium; sexual reproduction not 

 observed: 2 species; both in America. 



P. calif ornica Shaw. Cells 64 or 128, half of which are vegetative : 

 California. 



P. illinoisensist Kofoid (Fig. 52). Cells 32, rarely 16 or 64, 4 of 

 which are vegetative, .12 mm. in diameter: Illinois. 



* See "On Platydorina," etc., by C. A. Kofoid, Bull. 111. St. Lab., Vol. 5, 

 p. 419, 1899. 



t See "On Pleodorina IlUnoisensis," etc., by C. A. Kofoid, 111. St. Lab., 

 Vol. 5, p. 273, 1898. 



