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G. P. BIDDER 



the distance carried appeared to be proportional to the diameter 

 of the osculum, although, in consequence of the oscula used 

 having small range in size, this result was not so certain. The 

 rough formula indicated by the experiments is that, using 

 centimetres and seconds, the length of the jet approximates 

 numerically to twelve times the product of its initial velocity 

 and the diameter of the osculum. 



That among jets of equal velocity the distance carried should 



Text-fig. 5. 



Rhagon. 



be proportional to the oscular diameter, might also be expected 

 by elementary theory ; since per centimetre of length the 

 weight of water increases as the square of the diameter, while 

 the surface exposed to friction increases only as the diameter. 

 Consequently the ratio of the moving weight to the resisting 

 surface increases as the diameter, and with equal velocity 

 a jet 4 mm. wide may be expected to go twice as far as a jet 

 2 mm. wide. 



This consideration enables us to understand the advantage 

 gained by the union of many unicellular flagellates to make 

 one thimble-shaped Olynthus, or by the union of many Olynthi 

 opening into a central cloacal cavity to form a Ehagon (Text- 

 fig. 5) or a Sycon. Suppose, in Text -fig. 6, we unite a hundred 



