THE MANIPULATION AND IDENTIFICATION OF 

 THE FREE-SWIMMING MASTIGOPHORA 

 OF FRESH WATERS 

 LEON AUGUSTUS HAUSMAN, Ph.D. 

 Cornell University 



Not the least among the problems that confront the 

 worker in systematic protozoology is the identification 

 of the minute, free-swimming Mastigophora, representa- 

 tives of which occur in all cultures, often in great num- 

 bers both of individuals and of larger groups. The 

 writer's attempts to find some means of making their 

 identification easier and more certain have resulted in 

 llif working out of several methods of dealing with these 

 elusive forms, methods which have been used with suc- 

 cess in the laboratory examination of material. They 

 are here presented with the hope that they may be a simi- 

 lar assistance to others. 



For the purposes of identification it has been found 

 helpful arbitrarily to divide the Mastigophora into two 

 great groups, on the basis of size ; placing those the ma- 

 jority of whose species measure about 12 microns or less 

 along the antero-posterior axis in one group, and those 

 of greater magnitude in the other. It is among the spe- 

 cies in the first group that the difficulties in identification 

 seem usually to occur, and it is with this division, there- 

 fore, that this paper deals. 



The genera included within this first arbitrary division 

 fall within the first four orders of the mastigophora, 

 thus : 



SUBPHYLUM MASTIGOPHORA 



Order Mostadida 



Genera: Mastigamoeba 

 Cercobodo 

 Cercomonas 

 Physomonas 

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