PLATES 



Practically all of the illustrations for the following; plates, 65 to 82, 

 are the work of Mrs. Virginia Sewell, to whom the author is much 

 indebted for her careful attention to details and interested cooperation. 



The scale of enlargement is not indicated on the plates, except in the 

 Ctenostomata. but exact measurements are given for each species in the 

 text. 



