INVEETEBRATE PALEONTOLOGY. (505 



surface unknown ; aperture broad lunate-subovate, rather oblique ; outer lip 

 apparently reflexed ; umbilicus small or closed. 



Length, 1.05 inches; breadth, 1.12 inches; length of aperture, 0.77 

 inch . breadth of same, 0.54 inch; apical angle convex, divergence about 

 lori . 



This species resembles in form a shell described by Matheron under 

 the name Cyclostoma Lunelii (Cat. Meth. Fos. Depart, des Bouches-du-RhSne, 

 209. pi. 35, rigs 12-13), though its outer lip appears not to have been thick- 

 ened as in that species. As all the specimens we have seen of our shell are 

 casts, we have no means of ascertaining the nature of" its surface-markings, 

 nor are we quite sure it would fall within the genus Helix as restricted by 

 some of the more recent writers; though there can be no doubt in regard to 

 its belonging to that genus as generally defined. 



Locality and position. — Bad Lands of White River; from the White 

 River group. 



