ODONTOCYCLAS. 255 



ascending in front. Internal axis rather large, either form- 

 ing an open umbilicus or closed at the base, which is rimate. 

 Aperture vertical, rotund, having angular, parietal and colu- 

 mellar lamellae, upper and lower palatal and basal plicae, and 

 usually some smaller secondary lamellae and plicae. Angular 

 and parietal lamellae parallel, the former not curving into the 

 lip ; all teeth marginal or nearly so, and none entering deeply, 

 those of the lip standing on a callous rim. 



According to Pfeiffer, Schmidt says that the superior ten- 

 tacles of rossmaessleri appear as if somewhat broken and 

 thickened near the apices. 



Type 0. kokeilii (Em.). 



Distribution, eastern outliers of the Alps, in Carinthia, 

 Carniola and neighboring regions. 



Illustrated on plate 41. Odontocyclas is a peculiar genus 

 having some resemblance to Abida, Sandahlia, Anisoloma and 

 Paraboysidia; distinguished from all by its apertural folds, 

 which are marginal; not entering deeply. The lamellae also 

 do not enter far. The apical whorls are very minutely gran- 

 ulose, as in related genera. By the somewhat large columellar 

 axis Odontocyclas resembles Sandahlia. It is an isolated 

 group, not known fossil. 



Odontocyclas appears to have the habits of Abida, also 

 Hypselostoma and Boysidia, crawling on rocks (probably 

 limestone). It is like Sandahlia and Rupestrella, and the 

 much more distantly related Gastrocopta and Hypselostoma 

 in having the shell coated with slime and dirt. 



There are two species, distinguished as follows: 



a. Shell straightly pyramidal, umbilicate, delicately striate ; 

 with 6 larger teeth. 



b. Small denticles between the plicae of the lip. 



0. kokeilii, no. 1. 

 6 1 . No denticles between the lip plicae. 



0. k. mitescens, no. la. 



a 1 . Shell broadly ovate, imperf orate or nearly so, rib-striate; 

 7 larger teeth. 0. rossmaessleri, no. 2. 



