I I O PROTOZOA chap. 



II. Food taken in at a definite point or points, or by absorption, or 

 nutrition holophytic. 



1. No reticulate siliceous shell. Diameter under 500 fx (1/50"). 

 * Contractile vacuole simple (one or more), 

 (a) Colourless : reserves usually fat : holozoic, saprophytic or 



parasitic . . . .2. Protomastigaceae 



(/J) Plastids yellow or brown : reserves fat or proteid : nutrition 



variable : body naked, often amoeboid in active state (G. nudae), 



or with a test, sometimes containing calcareous discs 



(" coccoliths," " rhabdoliths ") of peculiar form (G. loricatae) 



3. Curysomonadaceae 



Chromulina Cieuk. ; Ghrysamoeba Klebs ; Hydrurus Ag. 



Dinobryon Ehrb. (Fig. 37, 11) ; Syncrypta Ehrb. (Fig. 37, 12) ; 



Zooxanthella Brandt ; Pontosphaera Lohm. ; Goccolithophora 



Lohm. ; Rhabdosphaera Haeck. 

 (y) Green, (more rarely yellow or brown) or colourless : reserves 



starch : fission longitudinal . . 4. Cryptomonadaceae 



Cryptomonas Ehrb. (Fig. 37, 9) ; Paramoeba Greeff. 

 (S) Green (rarely colourless) : fission multiple, radial 



5. VOLVOCACEAE 



** System of contractile vacuoles complex, with accessory formative 

 vacuoles or reservoir, or both. 



(c) Pellicle delicate or absent : pseudopodia often emitted : 

 excretory pore distinct from flagellar pit : reserves fat 



6. Chloromonadaceae 

 Chloramoeba Lagerheim ; Thaumatomastix, Lauterborn. 



() Pellicle dense, tough or hard, often wrinkled or striate : con- 

 tractile vacuole discharging by the flagellar pit. Nutrition 

 variable . . . . .7. Euglenaceae 



Eaglena Ehrb. ; Astasia Duj. (Fig. 37, 3) ; Anisonema Duj. ; 

 Eutreptia Perty (Fig. 42, p. 124); Trachelomonas Ehrb. (Fig. 

 37, 1) ; Gryptoglena Ehrb. 



2. Skeleton an open network of hollow siliceous spicules. Plastids 

 yellow. Diameter under 500 //. . 8. Siltcoflagellata 

 Dictyocha Ehrb. 



3. Diameter over 500 /x. Mouth opening into a large reticulate 

 endoplasm : flagella 1, or 2, very unequal. 9. Cystoflagellata 

 Noctiluca Suriray (Fig. 48) ; Leptodiscus R Hertw. 



B. Fission oblique or transverse : flagella two, dissimilar, the one coiled 



round the base of the other or in a traverse groove ; pellicle often dense, 



of numerous armour-like plates . . 10. Dinoflagellata 



Ceratium Schrank ; Gymnodinium Stein ; Peridinium Ehrb. (Fig. 46) ; 



Pouchetia Schiitt ; Pyrocystis Murray (Fig. 47) ; Polykrikos Biitschli. 



The Protomastigaceae and Volvocaceae are so extensive as to require 

 further subdivision. 



Protomastigaceae 



I. Oral spots 2. Flagella distant in pairs. . . Distomatidae 



II. Oral spot 1 or 0. 



