1897.1 NATURAL SCIENCES OF PHILADELPHIA. 11 



The deaths, on the 15th inst, of John H. Campbell and Charles 

 H. Banes, members, were announced. 



The Gastropod Radula. — Mr. Pilsbry spoke of the development 

 and specialization of the radula in streptoneurous Gastropoda, show- 

 ing that the law of mesometamorphosis, originally based upon ortho- 

 neurous forms (Helicidce 1 ), is equally applicable to the Prosobranchs. 

 His remarks were illustrated by black-board diagrams and a series 

 of specimens. 



January 26. 



The President, Samuel G. Dixon, M. D., in the Chair. 



Twenty-two persons present. 



Charles J. Pennock and Williams Biddle Cadwalader were 

 elected members. 



The following were ordered to be printed : — 



1 Guide to the Study of Helices, Man. Conch., ix, p. xiii, (1895). 



