1919] KofoidSwezy: Strehlonuistix strix 15 



plast of StrcbloDiasii.i: in superficial appearance, but possibly homo- 

 logous witli flagella and derived by modification from one or more of 

 them. There are four such lines in Holomastigotes (Grassi and 

 Sandias, 1893) giving rise to lateral cilia and pursuing a spiral- course 

 posteriori}' from what is probably an anterior blepharoplast. There 

 are, however, no large anterior flagella arising from this point. 



The form most nearly allied to Strrhlomastix appears to be 

 PyrsoinjnipJia by reason of the persistence of an anterior outgrowth 

 from the blepharoplast which may be homologized with flagella. How- 

 ever, it has lateral cilia arising from its spiral lines. These Strehlo- 

 mastix entirely lacks." This absence of the lateral ciliary coat justifies 

 the exclusion of Strcblomastix from the Trichonymphidae and renders 

 its retention in the Polymastigina necessary. However, it may be 

 regarded as closely related to that branch of the polymastigote stock 

 from wiiieh the Trichonymphidae originated. Streblomastix thus 

 forms a living link between the Polymastigina and the Trichonym- 

 phidae, linking the latter seemingly aberrant forms more closely and 

 definitely than heretofore to the Flagellata as its most highly special- 

 ized order. 



It is obvious that Streblomastix can not be allocated in the family 

 Hexamitidae and that its relationships with the Polymastigidae are 

 T-elatively remote. Even its inclusion in the Polymastigina is some- 

 what problematical. Its transfer to the Trichonymphidae is defensible 

 but reqiiires a profound modification in the definition of that order. 

 To set forth more strongly its intermediate position we have left it in 

 the Polymastigina and propose for it a new family, the Sti-eblonuisti- 

 gidae, as follows: 



Family Streblomastigidae fam. nov. 

 Polymastigina with spiral myonemes and anterior flagella. 



Streblomastix gen. nov. 

 Streblomastigidae with six anterior flagella and four leiotropic 

 myonemes. Type species Streblomastix strix sp. nov. from 

 Termopsis angusticollis "Walker. 



