292 



ROBERT T. HANCE 



Chart 1 On the axis of abscissas are marked the various sizes in^u while on the 

 axis of ordinates are placed the percentages. The heavy solid line represents the 

 multivacuoled race of paramoecium while the light broken line indicates the larger 

 sizes of a small two-vacuoled race and the light unbroken line is based on figures 

 obtained from fixed preparations of two-vacuoled animals in the Laboratorj' 

 collection. 



the percentage of animals with thi'ee and four vacuoles was 

 very high. The consideration of this phenomenon will be left 

 for future work. 



6. The vacuoles 



1. Location. So exactly are the contractile vacuoles located 

 that a single straight line parallel to the outline of the animal 

 might be drawn passing tln"ough the center of each. In a very 

 few cases I have found one or two vacuoles shghtly displaced 

 from the usual straight row condition (fig. 9). In the majority 

 of individuals the extra vacuoles are located in the posterior 

 part of the animals as can be seen from the drawings. In a few 



