42 



MISSOURI BOTANICAL GARDEN. 



of the Lagoon, later forming a green scum on the surface of 

 the Nymphaea pool. 



The cell remains motile long, finally becoming motionless, 

 assuming a spherical form and lying imbedded in a gela- 

 tinous secretion. The first division in the formation of young 

 zoospores is longitudinal, the next transverse. Dimensions, 



9.6-17/iX6.4-11.2/i, while active; 6.4-12.8/a resting. 



VOLVOCACEAE. 



Eudorina elegans Ehrenb. Fountain pond. Nymphaea 

 pool. Waterfall stream. Quiet water. Sept. to Dec. Colo- 

 nies were breaking up the early part of Dec. 



Gonium pectorale Miiller. Nelumbium pools. Nymphaea 

 pool. Arboretum pond. Producing auto-colonies Apr. 10. 



Pandorina Morum (Miill.) Bory. Fountain pond. Ne- 

 lumbium pools. Arboretum stream. Waterfall stream. 

 Nymphaea pool. Sept., Dec, Mar., through June. Produc- 

 ing auto-colonies abundantly in April and March. 



Pleodorina californica Shaw. Edge of Fountain pond. 

 Shallow water. Colonies were observed in perfect state the 

 last of September. During the first part of November they 

 lost their vegetative cells and the number of colonies 

 decreased. The colonies at this stage resembled Eudorina. 

 Sept., Nov, 



TETRASPORACEAE. 



Tetraspora gdatinosa (Vauch.) Desvaux. Arboretum 



pond. Rocks, west Lagoon. 



Ineffigiata neglecta W. and G. S. West. Fountain pond. 



Rare, 



Protococcales. 



PROTOCOCCACEAE. 



Chlorococcum infusionum (Schrank) Menegh. Lagoon. 



PROTOSIPHONACEAE. 



Protosiphon botry 

 (E3). Associated ^ 



abundance. In Mai 

 tain pond. May, abi 



(Kiitz.) Klebs. Cabbag 



mm 



Wallrothii in Nov. in 



bed 



In loess soil. 



