498 



llniversity of California. PMicaiions in Zoology [Vol. 20 



It is not always possible to procure amoebae, even from the caecum, 

 that will remain active for more than a few minutes on the warm 

 stage. At times, however, amoebae have been secured which have 

 exhibited typical movement for thirty minutes. The rea-sons for this 

 variation in activity are undetermined. 



Fig. A 



Froe-haiul sketches, sliowing progressive movement, of Councilmaina vniris 

 from rat. 



In progressive movement an amoeba may move as far as 500 

 microns in five minutes. Usually, however, the movement is less rapid. 



