TilK NAUTILUS. 1 41 



NEW SPECIES OF LYMJTJEA. 



BY F. C. BAKER. 



Lymnsea oioascoensis nov. sp. 



Shell small, elongated, turreted, rather thin ; color light horn ; 

 surface shining, marked by close-set lines of growth; in some speci- 

 mens there is a tendency to form raised, keel-like ridges, as in 

 malleated forms of Lymnsea; apex small, round, of the same color as 

 the rest of the shell; whorls 5^, shouldered, rather flat-sided; spire 

 elongated, sharply conical ; sutures deeply impressed ; aperture 

 roundly ovate, about two-thirds the length of the entire shell ; outer 

 lip thin, inner lip erect, causing the aperture to be almost continu- 

 ous ; columelhi rather broad, flattened, somewhat thickened by a 

 callus but without a plait; umbilicus round, wide and deep, exhibit- 

 ing one volution ; the base of the shell is roundly flattened. 



Length 8.50; width 3.50; aperture length 3.50; width 2.00 mill. 



Length 8.75; width 4.00; aperture length 3.50; width 2.00 mill. 



Habitat: Owasco Lake, N. Y., collected by Dr. Howard N. Lyon. 



This distinct little shell may be known by its turreted shell, long 

 spire and large, open umbilicus. Its nearest ally is desidiosa. 



Lymnsea bryanti nov. sp. 



Shell small, thin, robust, pointed ; color light horn; surface rather 

 dull, marked by rather indistinct lines of growth, but without im- 

 pressed spiral lines; the base of the shell is marked by several indis- 

 tinct spiral ridges, and the last whorl is malleated in some specimens; 

 whorls 4^-5, rounded, roundly shouldered, rapidly increasing in 

 diameter; the last whorl is large and quite convex ; spire acutely 

 conical, shorter than or as long as the aperture ; sutures well im- 

 pressed ; aperture elliptical or elongate-ovate; columella a trifle 

 thickened, without a plait, the callus turned back and appressed to 

 the parietal wall as in cubensis ; umbilicus distinct and rather widely 

 open. 



Length 7.50; width 4.00; aperture length 4.00; width 2.25 mill. 



Length 6.50; width 4.00; aperture length 4.00; width 2.00 mill. 



Length 6.50; widlb 4.00; aperture length 3.50; width 2.00 mill. 



Habitat, Alameda Co., California. Collection of Mr. Bryant 

 Walker. 



