710 



THI'J A.UEHH'AX NATURALIST 



[Vol. XL. 



the cartilages. Some little yielding may take place; but it must 

 be evident, from the above considerations, that the movements of 

 the radula are similar to, and dependent upon, that licking action 

 impressed upon the buccal cartilages in the way we have seen. . . . 



'•Thus tlie explanation here put forward has something more in 



(onuuon with that of Cuvier than with the later theory proposed 



by Professor Huxley .... 



"In the transparent bodies of some Heterojioda, Prof. Huxley 

 describes a chain-saw movement; so, if the framework remains 

 quite stationary, I can only suggest that the sliding of the radula. 

 over its support, which we saw as a secondary factor in the Limpet, 

 though impossible in the (.'uttlefish and highly im|)i'ob;tl)h' in the 

 Whelk, may in these animals have acpiiivd u'rrar. r inipnrianc,'." 



Tryon ('SI) in his Manual nf Cnnrhnh.,, , ,-.>,uinuc,l In PiUbiy i 



^ Wegmann ('84) describes the <,<lo,itoph<.rai apparatu,^ in HaHotis 



