5^ THE INVERTEBRATA 



1. The Zoomastigina never have starch or other amyloid reserves. 



2. They often have more than two flagella. This is very rare in the 

 Phytomastigina. 



3. With a single exception, ^ it has not yet been established that 

 syngamy occurs in any of them. 



4. Many of their parasitic members possess parabasal bodies. 



Order RHIZOMASTIGINA 



Zoomastigina with one or two flagella, and the whole surface of the 

 body permanently amoeboid. 



Mastigamoeba (Fig. 47 A). One flagellum; numerous, finger-like 

 pseudopodia. In fresh waters. 



Order HOLOMASTIGINA 



Zoomastigina with numerous flagella, and the whole surface of the 

 body capable of amoeboid action. 



Multicilia. Spherical, with 40 or 50 flagella scattered evenly over 

 the whole surface, at any point on which food can be ingested by 

 amoeboid action. A marine species vidth one nucleus; freshwater 

 species multinucleate. 



Order PROTOMONADINA 

 Zoomastigina with one or two flagella; amoeboid movement, if 

 present, not active over the whole surface of the body; and no extra- 

 nuclear division centre. 



Monas (Fig. 47 C). Two unequal flagella. Ingestion at base of 

 flagella. Except for absence of chromatophores much resembles 

 Ochromonas among the Phytomastigina and is probably related to 

 that genus. In fresh waters and infusions. 



Bodo (Fig. 47 D). Two rather unequal flagella, of which one trails 

 freely behind and is used for temporary anchoring. Ingestion at a 

 spot near the base of the flagella. In infusions and coprozoic. 



Oikomonas (Fig. 47 B). One flagellum. Ingestion of food as in 

 Monas. This genus bears the same relation to certain uniflagellate 

 Chrysomonadina that Monas bears to Ochromonas. In fresh waters 

 and soil. 



Trypanosomidae (Fig. 48). Parasites, with one flagellum ; a slender, 

 usually pointed shape; a strong pelHcle without ingestion spot; a 

 parabasal body; and no contractile vacuole. This family, which con- 

 tains many dangerous parasites of man and domestic animals, appears 

 to have originally infested invertebrates and to have obtained access 



1 Helkesitnastix, a coprozoic member of the Protomonadina, performs 

 hologamy. 



