MORPHOLOGY AND TAXONOMY OF MASTIGOPHORA 305 



Sub-order 3. Cystoflagellina. 



Two doubtful genera of Dinoflagellates — 



Form discoidal with minute flagellum. .Genus Leptodiscus 

 Form medusa-like ; with velum Genus Craspedotella 



Order IV. PHYTOMONADIDA. 



1. Four flagella; no firm membrane . Familj^ 1. PoLYBLEPHARiDyE 

 Usually two flagella; with cellulose mem- 

 branes 2 



2. Cellulose membrane a single piece 3 



Membrane in two valves Family 2. Phacotid^ 



3. With chromatophores 4 



Colorless forms Family 3. Polytomid^e 



4. Solitary or colonial; flagella two or four 



Family 4. Chlamydomonadid^ 

 Colony forms; two flagella Family 5. Volvocid.e 



Family 1. Polyblepharidse. 



1. With green chromatophores Genus Pyramimonas 



Colorless forms Genus Polytomella 



Family 2. Phacotidae. 



1. Bivalve shell distinct at all times. . .Genus Phacotus 

 Bivalve condition shown only during divi- 

 sion 2 



2. Shell with lateral ridges Genus Pteromonas 



Shell witliout lateral ridges Genus Coccomonas 



Family 3. Polytomidse. 



With rounded anterior end ; two flagella 



Genus Polytoma 

 With obliquely truncated anterior end . Genus Parapolytoina 



Family 4. Chlamydomonadidse. 



1. With four flagella 2 



With two flagella 3 



2. Individuals solitary Genus Carter ia 



Colonial forms Genus Spondyloniorum 



3. Cellulose membrane tight fitting 4 



Membrane separated by space from cell ... 6 



4. Cells elongate, spindle-form Genus Chlorogonium 



Cells spherical or ellipsoidal 5 



Cells cuboidal or lobate 7 



5. One large, cup-shape chromatophore 



Genus Chlamydomonas 

 Chromatophore band-form about periphery 



Genus Mesostigma 



6. Flagella pass through jelly of shell. .Genus Sphcerella 

 Flagella from protoplasmic strand at per- 

 iphery Genus Hcematococcus 



7. Lobate arm-like processes Genus Brachiomonas 



Variable mound-like excrescences on cell 



Genus Lobomonas 

 Family 5. Volvocidae. 



1. Colony flat; cells in one plane 2 



Cells united in spheroidal colonies 3 



2. Flagella directed from one surface only 



Genus Goniuin 

 20 



