LIMNEA FRAGILIS. 21 



SHELL oblong-conic, slightly umbilicated, 

 composed of six convex whirls, the surface of 

 which is frequently marked with irregular ele- 

 vated reticulations, unconnected with the fine 

 lines of growth, or the very minute spiral lines: 

 suture very distinct, but not deep: aperture 

 generally shorter than the spire, and sometimes 

 having a calcareous rim within the peristome. 



The characteristic shell has the irregular 

 elevated lines, and convex whirls, as figure 1. 

 The varieties are as follow: 



A. Smooth, whirls convex, fig. 3. 



B. Smooth, whirls flattened, figs. 4 and 11. 



C. Color dark, aperture irregular, fig. 6. 



D. Color light, aperture margined, fig. 7. 



E. Aperture simple, color dark brown, fig. 9. 

 The varieties D and E have the minute spiral 



lines very distinctly marked, but the irregular 

 reticulations are wanting: when these are pre- 

 sent, the surface is divided into series of facets, 

 which have been compared to those upon cut- 

 glass. 



COLOR various shades of brown and yellow- 

 ish-brown, aperture frequently margined with 

 chesnut. 



GEOGRAPHICAL DISTRIBUTION. Found in the 



