APPENDIX. 397 



Forming a spherical body : 

 Cilium solitary. 

 With a tail, Uroglena. 

 Without a tail. 

 Without eye-spot. 

 With special coats, Syncrypta. 

 With eye-spot. 



Gonidia dividing into clusters, Spharosira. 

 Cilia 2. 



No eye-spot, Synura. 

 With eye-spot. 

 Common envelope spherical. 

 Gonidia numerous, all over periphery, VOL vox. 

 Gonidia 8, in a circle at the equator, STEPHANOSPH^RA. 

 Envelope ellipsoidal, gonidia 16 or 32, perhaps stages 

 of Volvox or Pandorina. 



13. DESMIDIACE^;. Microscopic, gelatinous, green; cells 

 without siliceous coat; forms varied, as oval, crescentic, 

 cylindric, etc., with a more or less stellate appearance, 

 having a bilateral symmetry, the junction being marked 

 by a division of the green contents ; individual cells free 

 or grouped. Reproduction by division and by resting 

 spores produced in sporangia formed after conjugation of 

 two cells and union of their contents, and by zoospores 

 formed in the vegetative cells or in the germinating rest- 

 ing spores. 



I. CLOSTERIEJE. Cells single, elongated, never spinous, 

 often not constricted in the middle ; sporangia smooth. 



1. Closterium. Cell crescent-shaped, or much attenu- 

 ated at the ends, not constricted in the middle. 



2. Penium. Cell straight, not, or very little constricted 

 in the middle, rounded at both ends. 



3. Tetmemorus. Cell straight, constricted, notched at 

 ends. 



