194 PROCEEDINGS OF THE ACADEMY OF [May, 



Note on the Value of the Gastropod Apex as a Means of Classifieotion. 

 — Dr. Burnett Smith remarked that studies recently made among 

 Tertiary and recent Gastropods tend to show that the importance of 

 the "protoconch" as a means of generic discrimination has been 

 greatly exaggerated. An examination of the species of Pyrula with 

 rounded whorls (P. ficus, P. papyratia, P. mississippiensis, P. condita, 

 etc.) has shown that with slight exceptions the chief specific modifica- 

 tions have been introduced not into the later adult whorls, but into the early 

 whorls. On tracing the genus back in time it is seen that on the whole 

 the apices become smaller and the smooth whorls are more numerous. 

 Nevertheless we find that at the present day both the small (generalized) 

 and the large (specialized) apices are found. The Panamic form 

 (P. decussata) is furnished with the primitive type of apex, while the 

 Gulf and Caribbean representative (P. papyratia) has the large 

 specialized apex with but one smooth whorl. 



The Texas and Louisiana Lower Claiborne races of the species com- 

 monly known as Volutilithes petrosus constitute still another mono- 

 phyletic assemblage, though in this case a more restricted one. Here 

 it has been observed that again the chief modifications are exhibited 

 by the apical smooth stage, while the later ontogenetic stages remain 

 relatively unchanged. 



John W. Harshberger, Ph.D., spoke of the influence of chemicals 

 on the development of the bud. (No abstract.) 



May 2L 



Arthur Erwin Brown, D.Sc, Vice-President, in the Chair. 



Thirty-eight persons present. 



The Publication Committee reported that papers under the following 

 titles had been presented for publication : 



"The Polycystid Gregarines of the United States" (third contribu- 

 tion), by Howard Crawley (May 13). 



"A New Species of Athleta and a Note on the Morphology of Athleta 

 petrosa," by Burnett Smith (May 15). 



"New and Little-known Whelks from Northern Japan and the Kuril 

 Islands," by H. A. Pilsbry (May 16). 



" The Distribution of the North American Gordiacea, with Descrip- 

 tion of a New Species," by Thomas H. Montgomery Jr. (May 21). 



P. Chalmers Mitchell, of London, was elected a correspondent. 



The following were ordered to be printed : 



