1902.] NATURAL SCIENCES OF PHILADELPHIA. 505 



June 3. 

 Mr. Arthur Erwin Brown, Vice-President, in the Chair. 

 Twelve persons present. 



The death of George S. Schively, M.T>., a member, Sept. 28, 

 1901, was announced. 



Phylogeny of the Species of Fulgur with Remarks on an Abnor- 

 mal Form of Fulgur canaliculatum, and Sexual Dimorphism in 

 Fulgur carica. — Mr. Burnett Smith communicated some prelim- 

 inary results of a phylogenetic study of the genus Fulgur. The 

 ornamentation on the whorls shows that changes occur in going from 

 the protoconch to the adult whorl. In Fulgur the changes in orna- 

 mentation agree in general with those observed by the Countess 

 von Linden^ in dealing with marine gastropods in general. As in 

 most gastropods where the early whorls can be studied, transverse 

 ridges occur fii-st, except in certain forms where acceleration has 

 taken place. Tliese are followed by a spiral row of nodes or spines, 

 which in old age are apt to degenerate into a shoulder keel. Modi- 

 fications of these stages may occur, but they can usually be detected. 

 In the Miocene a tendency developed which resulted in the canal- 

 iculate division of Fulgur. This division is probably an offshoot 

 from the primitive non-canaliculate stock, of which F. carica is the 

 modern representative. On the following page is a rough scheme 

 showing the probable ancestry of the different races. 



The pyrum group seems to have sprung from a Fulgur canalicu- 

 latum precursor which had transverse ridges on the whorl following 

 the protoconch. In fact there is a Pliocene shell in the Academv's 

 collection which tends toward fulfilling the requirements of this 

 precursor. In all the young shells of the recent F. canaliculatum 

 which I have examined, nodes occur on the whorl next to the pro- 

 toconch and the transverse ridges are absent. This is probably a 

 case of acceleration. In the non-canaliculate Fulgurs the recent 

 F. carica shows well all tlie stages of ornamentation, from whorls 

 with transverse ridges to whorls in which the spines degenerate into 

 a shoulder keel. In the Caloosahatchie Pliocene both canaliculate 

 and non-canaliculate divisions gave rise to smooth, bulboiis^,var- 



1 Zeit. wiss. Zool, LXI, pp. 261-317. 



