Synopsis Fresh-Watkr Moli^usca 

 Subgenus ALASMINOTA Ortmann, 1914. 



61 



Shell elongated elliptical, rather small. Surface without sculpture. 

 Pseudocardinals delicate ; laterals nearly or quite wanting. Beak sculpturft 

 not heavy, consisting of four to six rather fine, sharp bars, the first one or 



Fig. 178 



two subconcentric, the following ones sharply double-looped, the posterior 

 loop smaller, separated from the anterior by a deep, sharp, re-entering angle. 



Type: Margaritann holstonia Lea, fig. 178. 



Subgenus PTEROSYNA Rafinesque, 183 1. 



Shell large, ovate-rhomboid, inflated in the post-basal region; beaks 

 much compressed; their sculpture sharply and strongly doubly looped; epi- 

 dermis dark, scarcely rayed ; teeth very heavy. 



Fig. 179 

 Type: AlasmodovJa roraplanata Bar., i^g. 179. 



