NEW MOLLUSKS FROM THE BAHA^IA ISLANDS. 



By Paul Bartsch 



Assistant Curator, Division of Molhisls, United States National Museum. 



Some time ago the United States National Museum received from 

 Mr. G. W. Pepper, of Providence, Rhode Island, a collection of 

 Bahama land moUusks for determination. Among these shells are 

 several forms which are sufficiently distmct from those heretofore 

 known from these islands to merit recognition. I have therefore 

 prepared the followmg descriptions and figures. 



wShortly after describing these shells, I had the pleasure of visiting 

 the Bahamas myself, and was able to make large collections there, 

 particularly on Andros Island, which is a collective term applied to a 

 number of minor keys separated by tortuous channels of varying 

 width and depth. Practically each key exammed, no matter how 

 small, providmg it bears vegetation, excepting those in the Tongue 

 of the Ocean, which are at tmies dashed over by waves, is mhabited 

 by Cerions of the glans group. Sufficient differentiation has taken 

 place on each key to enable one to distinguish the shells from the 

 different keys. On some of the keys a series of swales separate an 

 equal number of wooded elevations, each of which is occupied by a 

 different race of these shells. The question naturally presents itself, 

 to what extent are these forms constant ? Do they represent stable 

 races with fixed characters, or are they contmuaUy changing in 

 form ? It seems to me that our systematic treatment of this group 

 wiU have to depend upon the answer to these questions, for it 

 would be folly to waste time and paper in describing thousands of 

 forms if they are not constant. If they are changing, the question 

 still presents itself, do they pass tlirough a definite cycle of changes ? 

 Then the further question arises, are we dealing with a complex Men- 

 delian problem? At aU events it seems desirable to study the un- 

 derlymg factors responsible for the phenomena as they are repre- 

 sented, and until such studies have been completed it would be more 

 desirable to stop indiscriminate description of new species of Cerlon. 



I have probably a hundred so-called species which I might de- 

 scribe, of recent years' collecting, as distinct as any that have received 

 names in the past, which will wait for their designation until the 



Proceedings U. S. National Museum, Vol. 46-No. 2016. 



