34 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [BulL 



20. Colonies gelatinous, thread-like, discoidal or round, 



hollow or sack-like Spongomonas 



Colonies of dichotomously branching tubes. .Cladonionas 

 Colonies of many closely approximating, jelly-like 



tubes Rhipidodendron 



21. With two brown, band-like chromatophores 22 



With green chromatophores 23 



22. Spherical swimming colonies ; cuticle sometimes spiny 



Symira^ 

 Like the above but with a common jelly covering. . . 



Syncrypta 



23. Colonies commonly spherical 24 



Colonies not spherical 25 



24. Colonies of sixteen (rarely thirty-two) radially ar- 



ranged individuals, their inner ends reaching the 



center Pandorina* 



Colonies of sixteen individuals, separate from each 

 other, and lying near the wall of the jelly sphere. . 



Eudorina 

 Colonies of very numerous individuals in a sphere. . 



Volvox] 



25. Colonies of eight equatorially arranged individuals. . 



Stephanosphcera 

 Colonies somewhat ellipsoidal, of sixteen individuals, 



in four rows around a longitudinal axis 



Spondylomorum* 

 Colonies of four to sixteen individuals in a flat plate 



Gojiium 

 Description of Genera. 



Amphimonas Duj. 



Spherical to oval, or triangular. Posterior end elon- 

 gated into a thread-like stalk, which may be attached. 

 Two equal flagella arise at the anterior end close together 



iVo/vox is frequently included among the Flagellata, and certainly shows 

 resemblances to some of the genera belonging to this class. I have, therefore, 

 included it in this key, although I regard it as more closely related to the ALG^E. 

 Its description will be reserved for the paper upon the ALGiE, which will appear 

 later. 



