MICROSPORIDIA 343 



amoebula makes its way through the host's cell wall is not under- 

 stood. As a rule, the cytoplasm of a schizont takes stain more 

 deeply than that of a sporont. In the majority of species, the 

 youngest schizont is uninucleate. The schizonts multiply by simple 

 and repeated binary and multiple fissions and increase in number 

 within the cell. The nuclear division appears to be amitotic, though 

 presenting various aspects among different species. In a few species 

 such as Thclohania mccuadis, T. giardi, Toxogliigea mercieri 

 (Poisson, 1924), the division is said to be mitotic or promitotic. 

 Through multiplication, a large number of uninucleate schizonts 

 are produced, and ultimately each is considered as giving rise to a 

 uninucleate sporont. This change was reported to occur in Noscnia 

 bombycis (Stempell, Kudo), N. apis, N. bombi (Fantham and 

 Porter), A'. anopJielis (Kudo), N. marionis (Stempell), A^ fren- 

 zclince (Leger and Duboscq), TheloJiauia chcetogastris (Schroder), 

 etc. 



In other species, the youngest schizonts appear to be uninucleate, 

 and multiply by binary or multiple fission in number. From these, 

 binucleate schizonts ("diplocarya" of Debaisieux) are formed, as 

 a result of the nuclear division, without being accompanied by 

 cytoplasmic division. This change was noted in Thclohania nmlti- 

 spora, T. Hbrata, T. bract cata (Debaisieux and Gastaldi), T. 

 chironomi, Plistophora simulii (Debaisieux, 1928), Thclohania 

 legeri, Stcmpcllia (Kudo). These binucleate schizonts seem to 

 multiply in number by division. Finally the two nuclei fuse and a 

 uninucleate sporont is produced. 



In a number of species, the young schizonts appear to contain 

 two nuclei. This was reported in Thclohania corcthrcc (Schuberg 

 and Rodriguez), Pcrczia mcsnili, P.f legeri (Paillot), Noscnm 

 biniiclcatum (Weissenberg, 1926), and A^. nonagricc (Schwarz, 

 1929). These binucleate schizonts multiply by binary or multiple 

 fission, which results in the increase in number. Finally each 

 schizont gives rise to a binucleate sporont. 



According to Alattes (1928), the amoebula of Thclohania 

 ephesticc is first binucleate and multiplies in number by a binary 

 fission. Uninucleate schizonts are formed from these through 

 nuclear fusion, which also multiply by a binary or multiple division. 

 Later binucleated schizonts develop from them. The fusion of the 

 two nuclei in these binucleate schizonts results in the production of 

 uninucleate sporonts. 



