bartsch: classification of helicinidae 645 



impressed groove. Upon this group I will bestow the subgenerie 

 name Schistopinax with Geophorus (Schistopinax) siquijorensis 

 Bartsch as genotype. 



The other group has the main portion of the operculum, as in 

 typical Geophorus, but a strong lamella extends across the oper- 

 culum on the outside a little distance from the columellar border 

 dividing this into a large shallow spoon shaped area, and a deep 

 pit between the columellar border and the lamella. The group of 

 mollusks having these opercular characters are now assigned to 

 a new subgenus, Diplopinax, with Geophorus {Diplopinax) per- 

 acutissimus Wagner as genotype. 



Geophorus therefore breaks up into the three subgenera, Geo- 

 phorus, Schistopinax, and Diplopinax. 



The most highly specialized operculum is possessed by the 

 genus Kosmetopoma Wagner, which has the inside not unlike 

 Sulfurina, with the internal ridge quite low, while the exterior is 

 marked on the edge adjoining the outer and basal lip by several 

 dentate ridges. The type of this genus is Helidna amaliae 

 Kobelt. 



The mollusks of this genus are earth dwellers; i.e., they live 

 on the ground among the dead leaves about the base of trees 

 and rocks, but their favored place of abode is found in the 

 pockets, nooks, and crannies of honey-combed limestone in 

 shady moist situations. I have, on several occasions, picked 

 thousands from an area of a few square yards under such cir- 

 cumstances. During the rainy season they become quite active 

 and one may then find them crawling up the lower portions of 

 the bowl of trees and on fallen logs or rocks, while during the 

 dry period they are neatly wedged away in the crevices of the 

 rock and between chinks of bark and the leaf or moss-covered 

 base of trees. 



Key to the sections of the subgenus Geophorus 



Spiral sculpture present. 



Angle at junction of columella and basal lip present I 



Angle at junction of columella and basal lip absent II 



Spiral sculpture absent. 



Angle at junction of columella and basal lip present. Ill 



Angle at junction of columella and basal lip absent IV 



