126 



THE NAUTILUS. 



Lymnea linsleyi DeKay, N. Y. Moll., p. 72, pi. iv, fig. 74, 1843. 



Lymnea lecontii Lea, Proc. Phil. Acad., p. 112, 1864. 



In this species American conchologists .have confused several 

 seemingly valid species. Say's types (two specimens) preserved in 

 the Philadelphia Academy, came from South Carolina and agree 

 fairly well with Binney's figure 99, in Land and Fresh-Water Shells 

 of North America. The South Carolina specimens are a trifle nar- 

 rower and less rotund than specimens from the north. Humilis is of 

 good size, with regularly rounded whorls, a broadly conical spire, 

 impressed sutures, 5-5^ whorls, aperture elongate-ovate and a trifle 

 less in length than the spire. The last whorl is somewhat inflated, 

 and the umbilical chink very distinct, being more open in some 

 specimens than in others. The surface is marked by lines of growth, 

 and in some specimens from Maine by elevated spiral ridges. The 

 fine impressed sculpture of some Lymnteas (as columella) is absent 

 in this species, as well as in the others mentioned below. Typical 

 measurements are as follows : 



aperture length 4.50 



width 4.75 



width 2.75 mill. 



aperture length 4.50 

 aperture length 3.50 



width 2.75 mill. 



width 2.50 mill. 



Length 9.00 

 (Say's type.) 



Length 8.50 ; width 4.00 

 (Chicago.) 



Length 7.50 ; width 4.25 

 (Maine.) 



Small forms of Lymncea cubensis Pfeiff'er, resemble humilis ; 

 cubensis has a wider, more solid shell, a more open umbilicus, and 

 the expansion of the columella is broader and of a different form, as 

 is #lso the aperture. 



L. humilis is found from Maine to California, and from Canada 

 to Mexico. 



Lymncea parva Lea. 



Lymnea par v a Lea, Proc. Amer. Phil. Soc., II, p. 33, 1841. 



Lymnea curta Lea, Proc. Amer. Phil. Soc., II, p. 33, 1841. 



This is a very small species, in fact the sm/Ulest of the Lymnaeas. 

 It differs from humilis in its diminutive size, and in the very differ- 

 ent form of the shell, which is solid, translucent, turreted ; color 

 light brown or yellowish-white ; whorls 4^-5 ; these are more con- 

 vex than in humilis, caused by the more deeply impressed sutures ; 

 the spire forms an acute pyramid in some specimens, and a broad 



