SEX IN PROTOZOA 149 



(19 to 23). Prown/.ck's '"Bodo^' laccrtctc is probably identical with 

 Wcnvon's Vro^vctzekclhi Jaccrtac, now called Vrotcroinoiias hicertae, 

 and Alexeieff's Alphav/ajhis sp. has been identified by Woodcock 

 (1921) as the Spirouionas angiistiita described by the latter in 1916. 

 Prowazck interpreted his evidence as indicating reduction divisions 

 followed by fusion of nuclei, but Wenyon (1920) does not support 

 that interpretation, although he does show cell and nuclear fusion 

 (Fig. E, 24 to 28). It is probable that the reduction nuclei of Prowa- 

 zek \\ere the paranuclear bodies (formerly called parabasal bodies) 

 characteristic of this flagellate. Prowazek (1904b) also described "au- 

 togamy" in cysts of ''Bodo'' hicertae, but this is probably a misinter- 

 pretation, as indicated by Wenyon (1920). 



Dangeard (1910) described "autogamy" for Anthophysa vege- 

 tans. He believed that a nuclear division took place in weakened cells 

 which were unable to complete cell division. These binucleate ani- 

 mals encysted, a clear area appeared in the middle, later to disappear 

 and to be followed by nuclear fusion. Dangeard was not able to 

 follow the process of excystation. 



Order Folymastigma 



A half century ago some protozoologists were ready to accept 

 incomplete evidence as indicating sexuality; for example, for Tricho- 

 vioiias intestmalis (=T. hoviinis) and Lavjblia intest mails {=Giardia 

 laviblia) by Schaudinn (1903), and for Trichomastix lacertae, Tri- 

 chomonas ''intestmalis'''' from the rat, and HexamitJis ''intestinalis'^ 

 from Testudo graeca by Prowazek (1904b). In some cases develop- 

 mental stages of Blastocystis were confused with stages in the life 

 history of the flagellates. 



The account of cell fusion followed by encystment and the later 

 emergence of minute sporules for Tetrainitiis rostratiis by Dallinger 

 and Drysdale has already been mentioned. Bunting (1926) worked 

 out the life history of this flagellate, which showed that it could 

 transform completely into an amoeboid stage that could encyst. Only 

 amoebae encysted, and only amoebae came out of the cysts. Amoe- 

 boid stages readily transformed into flagellate stages and vice versa. 

 Under appropriate conditions either the amoeboid or the flagellate 

 stage could persist indefinitely. Bunting watched fusion of living 

 flagellates under the microscope (Fig. F, 1 to 7), and stained prepara- 



