10 proceedings of the academy of [1897. 



January 12. 

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

 Thirty-seven persons present. 



The Affinities of Floridian Miocene Land Snails. — Mr. Pilsbry 

 spoke of the Miocene Helices and Bulimi from the Silex-beds of 

 Tampa, Florida, stating that the fauna was of as purely Antillean 

 type as that of the Bahamas to-day. Helix latebrosa, instrumosa, 

 cnista, etc., belonging to the Plagioptycha section of the genus Cep- 

 olis. " Helix" haruspica proved to belong, as Dall had suspected, 

 to the genus Pleurodonta, and therein is about equally allied to 

 Cuban, Jamaican and Caribbean forms now existing. 



The Bulimiform snails of the Silex-beds numbered some four or 

 five species. They have a reflexed peristome, and a heavy deposit 

 upon the parietal wall, which is most strongly developed toward the 

 posterior angle of the aperture, but is there separated from the pos- 

 terior termination of the outer lip by a narrow channel, somewhat 

 as in certain European and Asiatic species of Buliminus, but entirely 

 different from the structure of the same part of the shell in Ameri- 

 can Buliiinilidoz. In a species from the island of Fernando Nor- 

 onha, however, an identical structure occurs. In fact, this species, 

 the Bulimus ridleyi of Smith, is so similar to some of the Miocene 

 forms of the Silex-beds that apart from size they are not readily dis- 

 tinguishable. There can be no reasonable doubt, therefore, that B. 

 ridleyi is a living representative of this Miocene group, preserved 

 practically unchanged on the remote island of Fernando Noronha, 

 while the group has been wholly crowded out of existence in the 

 continental faunas. 



The name Hjperaxdax was proposed for the group, which now in- 

 cludes the following species: 



Bulimulus (Hyperaulax) ridleyi Smith (type). 



Bulimulus (Hyperaulax) floridanus Conrad. 



Bulimulus (Hyperaulax) heilprinianus Dall. 



Bulimulus (Hyperaulax) americanus Dall. 



Bulimulus (Hyperaidax) steamsii Dall. 



All but the first of these being fossils of the Silex-beds. 



Hyperaulax may for the present be considered a subgenus of Buli- 

 iii a his; but the final position and rank of the group awaits invest- 

 igation of the soft anatomy. It belongs to Division II of the 

 speaker's classification of Bulimuli, having vertically wave-wrinkled 

 nepionic whorls. A similar reflexed peristome occurs in the sub- 

 genus Rhinus, but that group wholly lacks the other special features 

 of the aperture already alluded to. 



January 19. 

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

 Twenty-seven persons present. 



