INTRODUCTION 



29 



conditions not yet fully understood it becomes an active tailless 

 navicular organism which divides repeatedly, giving rise to minute 



M07 



Fig. 8. — Glaucoma (Dallasia) frontata. Vegetative individual. A, anus; BC, 

 buccal cavity; CV, contractile vacuole; LS, "ladder" system; LU, left undulating 

 membrane; M, mouth of buccal cavity; MOT, region of motorium; RU, right undu- 

 lating membrane; T, "tongue" in buccal cavity. (After Calkins and Bowling, 

 Arch. f. Protistenkunde, courtesy of G. Fischer.) 



