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THE AMERICAN NATURALIST 



[^•oL. XL 



against the immovable jaw where such an organ occurs, and, 

 without lingering at all in the bulb, pushed into the esophagus. 

 The radula suffers thereby no shifting of any sort (keinerlei Ver- 

 schiebung) upon its support." 



Pelseneer ( : 06, p. 7) in his volume on the ]Mollusca in Lankester's 

 Treatise, speaking of the odontophoral apparatus, has the following 

 remarks: "Applied to these cartilaginous pieces the radula, by the 

 action of special muscles, executes backward and forward rasping 

 movements." 



Again (:06, p. 89): "The radular ribbon is supported by a 

 system of pairetl cartilaginous pieces furnished with protractor 

 and retractor muscles the action of which causes the radula to 

 move to and fro and work like a rasp on the [)rey seized by the 



is conceived of in two very diiVerent ways by ino.tt of the ol)servers 

 that have up to the j»resent worked u})ou it: — 



