4 BULLETIGSr 181, UNTTEO SITATES NlATTOOSTiAIL MUSEUM 



Genus FARCIMEN Troschel 



1S47. Farcimen Troschel, Zeitschr. Malak., vol. 4, p. 44, in part. 

 1847 (November), i^a rc/w? ew. Hermannsen, Indicis generum malacozoorum primor- 

 dia, vol. 1, p. 439. (Type designated, Cyclostoma tortum Wood.) 



Typical Farcimen is known only from Cuba, where it is widely dis- 

 tributed and presents considerable variation in shell shape and sculp- 

 ture. In shape it varies from ovate to elongate-conic. The sculpture, 

 following an initial smooth nuclear portion, may be smooth, axially 

 lirate, or even ribbed, spiral threads may be present, or the surface 

 may be pitted as in the Farc'iTnen alutaceum, group. The peristome is 

 heavily reenforced by a thickening and is reflected. The operculum 

 consists of a simple, thin, multispiral chrondroid plate. 



Type: Turho tortus yVood= Farcimen (Farcimen) tortum (Wood). 



The anatomy of F. (F.) vinalense scopulorum is described under 

 that subspecies, p. 34. 



All members of the genus Farcimen are mulch-dwellers; they find 

 their optimum habitat where dead leaves and vegetable detritus be- 

 come mixed with sand or soil at the base of stone walls or paredones or 

 dead trees. Here usually there is sufficient moisture to furnish ideal 

 conditions for the development of fungi, upon whose mycelial threads 

 they seem largely to subsist. Living specimens are therefore rarely 

 seen on the surface. It is only on wet days or dewy nights that they 

 appear to come from their hidings and may then climb for some feet 

 above the level normally occupied by them. Usually they burrow 

 below the surface and have to be sought by grubbing for them. For 

 these reasons the shells of most species are partly covered with dirt 

 when found. 



This leaf-mulch dwelling does not tie them to the restricted habitat 

 that the calciphilous annularids are forced to effect. We therefore 

 find the various species occupying a much more extended territory than 

 is the case in the annularids. They are not confined to the moun- 

 tains but are equally at home in the plains, where their worst enemy 

 is agriculture, which usually destroys their favorite habitats. Their 

 greater abundance in the rough hilly country at present merely means 

 that man's activities so far have failed to dispossess them. 



The absence of strongly developed sculptural characters makes the 

 genus Farcimen a rather trying group to handle taxonomically. 

 Words alone seem inadequate to define convincingly our concept of 

 species and races. Fortunately, by the use of the camera we are able 

 to portray the characters far better than mere word pictures can accom- 

 plish. We hope, therefore, that by consulting both descriptions and 

 figures our contentions will be made clear. 



