LYMNZIDZ OF NORTH AMERICA. 161 
Ecotocy: Not recorded. Hemphill says: “Found on the shores 
of the above lake in November, 1889. I found two living specimens 
in the lake.” 
REMARKS: Occidentalis is one of the most characteristic of the 
American races of Lymnea. The short, acute spire with its peculiar 
shoulder just above the suture, the suddenly expanded body whorl 
with its pronounced shoulder, easily distinguishes it. Its nearest rela- 
‘tive is sanctemarie, in which the whorls are not angular and the spire 
is longer. There is some distortion in the aperture, especially in the 
anterior margin; the spire also varies in height. 
Occidentalis is strongly suggestive of some individuals of the 
European lacustris Stud., but in occidentalis the spire is longer and 
more acute and the shoulders of the whorls are sharper than in the 
specimens of lacustris which the writer has examined. Some of the 
short-spired forms of European stagnalis are beautifully illustrated by 
Nordenskiold in Bihang till Kong. Svenska Vetenskaps-Akademiens 
Handlingar, Band 26, Afd. IV, No. 11, Tafl. 1. The plate well illus- 
trates the large amount of variation to which stagnalis is subject. 
Lymnea lepida Gould. Plate XXIII, figures 6-7. 
Limnea lepida Goutp, Proc. Bos. Soc. N. H., II, p. 211, 1847; Moll. Wilkes 
Exp., p. 121, figs. 141, 141a, 1852——Binney, Check List, p. 12, 1860.—Cpr., Rep. 
Brit. Ass., 1864, p. 673—Tryon, Amer. Journ. Conch., I, p. 247, 1865—Brnney, 
LE & F-W. Sh. N. A., Il, p. 29, fig. 33, 1865.—Coorrr, Proc. Cal. Acad. Sci., 
IV, p. 95, 1870.—Tryon, Con. Hald. Mon., p. 93 (67), pl. 16, figs. 12, 13, 1872.— 
Cpr., Smith. Mis. Coll., p. 159, 1872—Strarns, Proc. Nat. Mus. XIV, pp. 101, 
102, 1891; N. Am. Fauna, VII, p. 275, 1893; Proc. Nat. Mus., XXIV, p. 291, 
1901.—Kerep, West. Amer. Sh., p. 314, 1904. : 
Lymnea lepida Dat, Land & Fresh-Water Moll., p. 67, fig. 43, 1905. 
Limnea lepida Goutp, Otia. p. 41, 1862—Cartton, Proc. Cal. Acad. Sci., 
IV, p. 51, 1869. 
SHELL: “Very fragile, elongated, very acutely conical, subumbili- 
cate, pale horn color; whorls five, oblique, moderately convex, forming 
an accuminated spire; suture moderately impressed; surface smooth 
and shining, lines of growth faint, and when examined by a magnifier 
they are found to be rendered somewhat zigzag by distant, revolving 
furrows, which cross them. Aperture large and expanded, nearly semi- 
circular, half the length of the shell; outer lip expanded; columella 
having a very strongly marked sharp fold, and broadly covered with 
thin callus, which not being closely appressed at the umbilical region, 
leaves a small chink. Length, 3/5, breadth 1/4 inch.” (Gould.) 
Length. Breadth. Aperturelength. Breadth. 
12.00 5.25 6.00 2.75 mill. Type (5541). 
12.00 6.00 oer sweet \o. etaould: 
