336 RESEARCH IN PROTOZOOLOGY 



Krempf), O. siiuiilii (Debaisieux, 1928) and Tcluiyxa glugei- 

 formis (Leger and Hesse.) 



Four nuclei were reported to occur in Gliigea anoniala, Nosema 

 bombycis (Stempell) and Thclohania giardi (Mercier). The above 

 tabulation would seem not to support Debaisieux's (1928) recent 

 generalization, which makes a part of an excellent paper, that 

 the spore of the species which possess unisporoblastic sporonts, 

 contains a binucleate sporoplasm, while that of the species which 

 possess polysporoblastic sporonts, a uninucleate sporoplasm. 



3) The structure and function of tJie polar filament. The polar 

 filament of the microsporidian spore was first discovered by 

 Thelohan (1892) in Glugea anoniala. Although it had frequently 

 been compared with the tubular thread of the ncmatocyst of the 

 coelenterates, it was Stempell (1909) who supposed that it was 

 probably tubular in structure. Strickland and Morgenthaler agreed 

 with Stempell. Oshima (1927) repeated the writer's observation 

 on the filament-extrusion of the spores of Nosema bombycis 

 (Kudo, 1918) by means of hydrogen peroxide and claimed to 

 have seen evidences which led him to consider the filament is 

 tubular by careful examination under a darkfield microscope. 



As to the function of the polar filament, it is generally agreed 

 that it serves as a temporary anchoring apparatus of the spore in 

 the gut lumen of a new host. Korke (1916) thought further 

 that it may serve to conduct the amoebula to a distant part of the 

 host tissue. Ishiwata (1917) noted a round knob which seemed 

 highly adhesive at the end of the extruded filament of Nosema sp. 

 Morgenthaler (1922) observed often in Nosema apis a fluid mass 

 at the end of the extruded filament. In Stempellia magna, Kudo 

 (1924) noted occasionally a thick point at the end of the filament 

 and considered it as the material of the filament which was spread 

 out by the breaking of the structure. Zwolfer (1926) recognized 

 the viscosity of the surface of the extruded filament of P.listophora 

 blochinanni. These observations strengthen the view that the fila- 

 ment serves for bringing the spore close to the host tissue. Ac- 

 cording to the same observer trypsin dissolved the filament com- 

 pletely after twenty-four hours. Oshima (1927) noticed that the 

 extruded polar filaments of Nosema bombycis were digested by 

 the digestive fluid of the silkworm larva in two to five sec- 

 onds and considered that the filaments penetrate through the 

 epithelial cells of the alimentary canal of the host larva and dis- 



