34 PROTOZOA 



4. Entosiphon Stein. Body ovate, with 2 flagella of nearly equal 

 length, one of which trails behind, a deep ventral furrow and a very 

 deep pharynx: 2 species. 



E. sulcatum St. (Fig. 40). Length .02 mm.: in fresh and salt water. 



Order 8. PHYTOFLAGELLIDA. 



Flagellates which include most of those forms with holophytic or 

 saprophytic nutrition, and are often classed as plants; most of them 

 are enclosed in a cellulose shell or jelly; yellow, green or brown chro- 

 matophores usually present ; very many are colonial : 4 suborders. 



Key to the suborders of Phytoflagellida here described : 



tti Yellow chromatophores usually present 1. Chromomonadina 



ttz Green chromatophores usually present. 



hi Mostly non-colonial ; 2 or 4 flagella 2. Chlamydomonadina 



62 Colonial ; 2 flagella 3. Volvocina 



Suborder 1. CHROMOMONADINA. 



Flagellates with a delicate cuticula and often somewhat amoiboid, 

 which are usually enclosed in a shell or jelly, and are often colonial; 

 yellowish or bluish chromatophores and 1 or 2 flagella present: 2 

 families. 



Key to the families of Chromomonadina: 



«i Color yellowish ; no pharynx present 1. Cheysomonadidae 



Oa Color blue, green or brown, or colorless ; deep pharynx present. 



2. Cryptomonadidae 



Family 1. CIIRYSOMONADIDAE. 



Body usually with a shell or in a jelly, with 1 or 2 flagella and always 

 with 1 or 2 yellowish chromatophores, and with or witliout eye-spots; 

 nutrition usually holophytic: 15 genera. 



Key to the genera of Chrysomonadidae here described : 



fli Body in a shell which it does not fill 1. Dinobryon 



Oj Body in a shell which fits it closely. 



hy One flagellum 2. Mallomonas 



62 Two flagella. 



Ci Flagella of equal length 3. Synura 



c. One flagellum long, one short ; colonial 4. Uroglena 



1. Dinobryon Ehrenberg. Free-swimming branched colonies, each 

 individual of which is in a transparent cup-shaped shell which springs 

 from just inside the opening of the shell next behind it; 2 flagella of 

 unequal length, 1 or 2 yellowish or brownish chromatophores, and an 

 eye-spot present: 3 species; in fresh water. 



