160 FRESH-WATER ALG^ OF THE UNITED STATES. 



diiiDi sixty-four spindle- or pear-shaped spermatozoids are devel- 

 oped of light green tint with colorless beak bearing two cilia, 

 (Kirch.). 



Asexual propagation takes place by the division of the cells 

 into 16-32 parts, each of which produces a new coeiiobium. 



EUDORINA STAGNALE, Wolle. 



Coenobium spherical, usually composed of thirty-two 

 globose cells arranged more or less regularly around the 

 inside of the walls ; the cilia pass through the tegument 

 and by constant vibration the coeuobium is kept in activity. 

 They are very variable in size, due to age, reckoned by 

 hours, from their escape from the mother cell. 



Diameter, 25-200 //. 

 Diameter of cells, 5-18 //. 



This plant is easily confounded with Pandorina morum. 

 The feature mainly to be relied upon is the arrangement of 

 the cells ; in Eudorina they are more or less regularly placed 

 around the inside of the walls ; in Pandorina they are more 

 densely clustered, often grape-like, nearly filling the cavity 

 .to the center. 



Found this plant repeatedly in pools filled by rains ; the 

 water was green with the multitude of coenobia it contained, 

 all spherical, ranging in size as indicated above. The mul- 

 tiplication is asexual and very rapid. 



The plant is unlike the only European species E. elegans, 

 Ehrb., in that it is not oval in form, and the cells are much 

 smaller. 



Plate CLI1, figs. 11-21. Fig. 11, a coenobium of sixteen 

 cells ; fig. 12, cells dividing, making thirty-two ; fig. 13, a 

 matured sphere, ready to break and scatter the cells, devel- 

 oping young coenobia ; figs. 14-21, various stages of develop- 

 ment of cells, all in active motion ; figs. 22, 23, spermatozoids. 



Genus 34, PANDOBINA, Ehrb. 



Coenobium globose, or subglobose, invested by a colorless, 

 gelatinous tegument ; cells green, granulose, globose ; 8-16-32-64 

 in a coenobium, each enclosed in a thin membrane and furnished 

 at maturity with two cilia ; often crowded in the coenobium 

 and for the time polygonal. 



Propagation sexual, by the conjugation of zoospheres. Cells of 

 a coenobium divide into eight daughter cells, these are scattered 

 and conjugate with similar cells from other coenobia ; they flow 



