454 0. CLIFFORD DOBELL. 



the nucleus^ arranges itself there at right angles to its 

 original position^ and the chromatin passes along it forming 

 a nucleus at each end. 



Unfortunately, in spite of much careful observation, I 

 was unable to ascertain whether conjugation occurred or not. 

 InT. lacerta) only autogani}^ occurs, and has been very care- 

 fully worked out by Prowazek in his excellent paper on 

 parasitic flagellates. I have frequently seen two individuals 

 apply themselves to one another for a short time, but they 

 always separated without any conjugation taking place. In 

 some cases a very delicate cyst wall was formed, the animal 

 becoming globular, and a number of refractive bodies were 

 developed inside. In the course of a few hours, however, 

 these forms always disintegrated. 



Degeneration and Death. 



As already mentioned, it was found possible to keep the 

 organisms in cultures for 120 days, but no longer. The 

 animals all underwent degenerative changes, and finally died. 

 A very great variety of forms occurred among those animals 

 which were degenerating. The following is the course of 

 events which usually took place, though many variations 

 were seen. First, the animals cease to move from place to 

 place. Movements of the flagella continue, but at a slower 

 rate, the animal remaining approximately in the same 

 position. At this period the posterior flagellum frequently 

 shows a tendency to become adherent to the body, a 

 delicate membrane uniting them together [see text-fig. 2, a]. 

 In this condition the creature is almost indistinguishable 

 from a Trichomonas — a genus which differs from 

 Trichomastix in possessing an undulating membrane 

 (often with a short free flagellum) in place of the posterior 

 flagellum. This adhesion of the posterior flagellum soon 

 becomes more extensive, and finally the flagellum is com- 

 pletely merged in the protoplasm of the body. The move- 



