13 

 LIMNEA MEGASOMA, Say. 



Plate 3.— Fig. 1—3. 



L. testa maxima, inflata, ruftl; spira acuta, non longitudo 

 aperturoe habente: anfractibus quinis convexis: sutura 

 impressa, apertura subovata; columella alba, profunde 

 plicata. 



SYNONYMS AND REFERENCES. 



Lymneus megasomus, Say. Long's Expedition to the 

 source of St. Peter's river, &c, vol. ii. p. 263, pi. xv. 

 fig. 10. 



DESCRIPTION. 



Animal blackish, — Binney. 



Shell very large, oval, inflated, and rather 

 solid; composed of five convex whirls: the lines 

 of growth are coarse, crossed by very fine, and 

 almost obsolete, transverse lines: suture deep: 

 spire short, and frequently much eroded, in 

 large shells: aperture oblong ovate, capacious: 

 fold on the columella well marked. 



Color of the shell, yellowish-brown; within, 

 reddish-brown. 



Geographical Distribution. Found in the 

 North-west Territory, Say: (north latitude 



