PARASITIC EUGLENOIDIDA 285 



the intestine. He points out that the allied Astasia captiva described by 

 Beauchamp (1911) from a turbellarian Catenula lemnce was more truly 

 parasitic, as it perished after removal from its host. AlexeiefE (1912/) 

 further records the presence of Astasia mobilis in a species of Cyclops. It 

 occurred not only in the intestine, but also in the developing embryos in 

 the egg sac, a fact which led Alexeiei? to express the view that it might 

 be transmitted hereditarily from host to host, and to restate Biitschli's 

 theory that Sporozoa may have evolved from these or allied flagellates. 

 Hegner (1923c) has given a description of Euglenoids studied by him in 

 tadpoles in America (Fig. 134). One form had a single flagellum like the 

 common free-living type Euglena spirogyra, while another possessed three 

 flagella. To the latter Wenrich (1923) has given the name Euglenamorpha 

 hegneri. It appears to be as truly parasitic as other Protozoa in the 

 intestine. It does not survive when removed from its host for any 

 length of time, but is readily passed from tadpole to tadpole by feeding. 

 Hegner also noted the presence of a species of Phacus. The three 

 types agreed with one another in the possession of green chromatophores 

 and bright red stigmata. Another form discovered in tadpoles of Lepto- 

 dactylus ocellatus of Brazil has been placed in a new genus Hegneria by 

 Brumpt and Lavier (1924). The single species, H. leptodactyli, varies in 

 length from 40 to 50 microns and has seven flagella. There is a large 

 anterior vacuole across which the intracytoplasmic portions of the seven 

 axonemes pass to end in seven blepharoplasts on the posterior wall of the 

 vacuole. 



2. SUB-GLASS: Zoomastigina Doflein, 1916. 



A. Monozoic Forms. 



1. Order: PROTOMONADIDA. 



As already remarked, the flagellates included in this order (=Proto- 

 monadina Blochmann, 1895) are forms of relatively uncomplicated 

 structure. They are monozoic, and possess a single nucleus and one or 

 more flagella, each of which has an axoneme arising from a blepharoplast 

 situated upon the nuclear membrane or separated from it. In the latter 

 case there is often a complex structure, the kinetoplast, made up of a 

 body called the parabasal and one or more blepharoplasts. The axoneme 

 forms the central core of the flagellum. It arises from the blepharoplast, 

 and usually takes a straight course to the surface of the body, whence it 

 enters the flagellum. Sometimes, however, when the surface of the body 

 is reached, it passes along the surface for some distance before entering the 

 flagellum, and the line of attachment may be raised into a thin membrane. 

 In some forms the cytoplasm at the anterior end of the body is raised 



