THE 



AMERICAN NATURALIST 



Vol. XLI Sepiemher, 1907 No. 489 



THE STRUCTURE OF CILIA, E.sPECI VEL^ I\ 

 GASTROPODS 



LI'OXAin) W. WILLIAMS 



the liope that thev niav coiiinhute to tlie solution of the (iiHicult 

 prolilem of the .structure ot ciha. 



"\^hlle lookuig over fresh niaruie plankton tnun NarrauaiiM'tt 

 Bav, we came upon an unidentified hnr connnon larva ot a pnuo- 



