712 



THE AMERICAN NATURALIST 



[Vol. XI> 



motion of the radula over the cartilage as a hand over a pulley is 

 in no way "sehr beschninkt," for two to three centimeters of the 

 length of the ribbon play back and forth over the head of the 

 cartilage. One can easily convince oneself of the large excursions 

 of the radula by placing one's finger tip in the mouth of an animal 

 that has been placed in the alcohol-turpentine mixture, and that 

 is consecjuendy in no pleasant mood. 



While Oswald states he made some observations on the living 

 animal, he makes no reference to any detailed artificial stmuilation 



are, it seems, drawn to a considerable degree from the anatomy 

 of the parts. 



Plate ('93) gives a brief dcs(Tij)tion of the odontophoral appara- 



niiiMii. though since he spt^aks of rctnictors and protractors of 

 flic I'adiila. he |)n)l)ahly accepts a slidiiiu' action of that organ. 



Ainaudnit (''.»M in a lengthy pai)er upon the anterior part of the 

 alimentary canal in gastropods makes a comparative study of the 

 odontophoral apparatus as found in this group of molluscs. He, 

 however, does not describe that of Sycotypus. On page 145 of 



