454 University of Calif ornm Publications in Zoology [Vol. 20 



The locomotion of Menoidium is characteristic, since the smooth 

 gliding type of movement found in many euglenoids is lacking. There 

 is a rotation to the right, but this is accompanied by an oscillation 

 of the body on its minor axis, producing an apparently awkward type 

 of locomotion ; yet this locomotion is evidently effective enough, since 

 the flagellate is capable of traveling more rapidly than the much 

 larger Euglena that occurs with it. 



Although encysted forms are mentioned by Lemmermann (1913), 

 the evidence for their occurrence in the cultures under observation 

 is inconclusive. Several possible cases have been found in stained 

 material, but owing to the fact that the cultures have contained 

 several other flagellates positive identification of these cysts as those 

 of Menoidium has not been possible. In this connection there might 

 be mentioned a peculiar case of an individual which apparently 

 contained three normal nuclei, one in the center of the body, the 

 second anterior, and the third posterior, to the first ; since this was 

 the only case discovered, its significance has not been determined. 



NUCLEAR DIVISION 

 The Resting Stage 



The resting nucleus of Menoidkim incurvum (pi. 40, fig. 7) con- 

 tains a more or less centrally located endosome, around which the 

 chromatin occurs in the nodes of a linin network. With the use of 

 counterstains, siich as Bordeaux red, after haematoxylin, the network 

 is lightly stained, while the chromatin masses are deeply stained. 

 This granular condition of the chromatin merges gradually into that 

 of the coiled chromatin threads of the early prophase, so that it would 

 be exceedingly difficult to determine just when the prophase begins. 



Contrary to the observations of Belaf (1916), Hartmann and 

 Chagas (1910), and Haase (1910) on various euglenoids, the endo- 

 some of Menoidium shows no centriole at this or any other stage of 

 mitosis. My haematoxylin preparations vary from deeply stained 

 to almost totally destained ; also a number of anilin nuclear stains 

 and counterstains after haematoxylin have been used ; yet none of 

 these brings out anv structure resembling a centriole. 



