LAURIA. 45 



Lauria minax Boettger. Jahrb. Nassau. Ver. f. Naturk., 

 Wiesbaden, xlii, p. 237, 319, pi. 6, f. 2. Upper Oligoeene, 

 Chattien: Landschneckenkalk, Hochheim. L. minax micro- 

 doma Bttg., I. c, is merely a deformed specimen. 



Key to Subgenera and Sections of Lauria, 



a 1 . Aperture having only angular and columellar lamellae in 

 the adult stage, the columellar often immersed or obsolete, 

 or rarely both are wanting. 



b 1 . Shell unicolored, only weakly striate. Subgenus 



Lauria proper, p. 45. 

 b~. Shell banded or bicolored, distinctly striate. Sub- 

 genus Petrarca, no. 51. 

 a 2 . Angular, parietal, columellar and palatal teeth present. 

 Subgenus Leiostyla, species 15-55. 



b 1 . Parietal lamella higher (i. e., projecting into the 

 mouth further) than the angular. Section Wollas- 

 tonula. 

 b 2 . Parietal lamella not higher than the angular, gener- 

 ally lower. 



c 1 . Parietal lamella emerging about as far as the 

 angular ; numerous teeth, all emerging to peri- 

 stoma. Section Scarabella. 

 c 2 . Parietal lamella not emerging so far as the 

 angular. 



d 1 . Diameter about two-thirds of the length ; 

 whorls not more than 5y 2 , with lamellar 

 ribs; parietal lamella minute or want- 

 ing. Section Mastula. 

 d 2 . Diameter relatively less, or whorls more 

 numerous. Section Leiostyla s. str. 



Keys to species may be found under Lauria and Leiostyla, 

 the latter following species no. 14. 



Subgenus Lauria proper. 



Shell perforate and deeply rimate, cylindric-tapering to 

 ovate, smoothish or finely striate, the aperture having a small 



