202 proceedings of the academy of [1898. 



April 5. 

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

 Seventeen persons present. 

 The death of Oliver A. Judson, M. D., a member, was announced. 



April 12. 



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



Twenty-six persons present. 



Prof. Pilsbry made a communication on the natural history 

 of slugs. (No abstract.) 



April 19. 

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

 Nineteen persons present. 



The Function of the Radula. — Mr. H. A. Pilsbry spoke of a 

 radula of the gastropod Nerlta peloronta exhibited by Mr. Keely, 

 mentioning its great length compared to that of the animal, and the 

 large number of similar teeth at the margins. The modifications 

 found by Fischer in the radula of Neritopsis and by the speaker in 

 that of Orthomesus and the Helicidre indicate that specialization in 

 the Rhipidoglossa and Pulmonata has proceded from the median 

 line of the radula outward, the outer teeth being the last to be 

 modified, and therefore of value as indicating the ancestral con- 

 dition ; this mode of modification being probably the result of the 

 greater functional activity of the median portion in feeding, due to 

 the rounded shape of the subradular cartilage. 



Mr. Calvert stated that the position of the radula in squids 

 recently dissected by him seemed to preclude the use of that organ 

 as a rasp, as described for snails. 



Mr. Pilsbry replied that he had not observed any cephalopod 

 feeding, but supposed that the radula here acted as an aid to 

 deglutition, crowding the fragments, taken in the beak, down the 

 oesophagus. 



Dr. Chapman observed that he had often observed squids eating 

 fish, and the beaks alone were used to bite the prey. He further 

 alluded to the impossibility of keeping squids in aquaria owing to 

 their incessant activity. They constantly dart against the glass 

 and soon die from the mutilation ensuing. 



