PLATES 



EXPLANATION OF PLATES 



All of the figures represent a magnification of about 3,000 diameters as they 

 are reproduced, except text figures 2, 4, and 7, which were drawn at about 3,000 

 diameters and reduced by |. The camera lucida was used for drawing together 

 with a xV oil immersion (B. & L.) and a no. 15 ocular. 



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