LYMNZIDZ OF NORTH AMERICA. 327 
callus. Attention to these points will usually separate the two forms. 
immature specimens of both species are sometimes difficult to distin- 
guish, but there is little difficulty in the case of fully adult shells. In 
some individuals of elodes the spire is shortened, the specimens of 
this kind resembling small, narrow forms of palustris. 
The figure of elodes in Binney is very poor, scarcely representing 
this form correctly, judging by the type, being too wide across the 
body whorl. Say may have included the wider, long-spired palustris- 
like forms in his elodes, but there is no question concerning the identity 
of the typical elodes. Say’s figure in the American Conchology (plate 
XXX, figure 34, of this volume) does not exactly fit the type specimen 
in the Philadelphia Academy, which is narrower and like the 
figures on plate XXXIV, and similar to Haldeman’s figure 2 
on plate 7. DeKay’s figure 76 on plate 4 correctly represents 
certain forms of elodes. Say’s umbrosa is undoubtedly a syno- 
nym of elodes (see Say’s figures on plate XXX, figures 32, 33), 
the two type specimens in the Philadelphia Academy being almost 
indistinguishable from the type of elodes. It has generally been placed 
in reflexa, but it lacks the characteristic twist, besides the peculiarities 
of the spire whorls mentioned above. A comparison of Say’s original 
figures on plate XXX with the figures on plate XXXIV will show this 
relation clearly. Haldeman plainly indicates the differences between 
reflexa and umbrosa, but places elodes in the synonymy of palustris, 
in which he has been followed by Binney and later writers. Michigan- 
ensis appears to be the immature state of elodes, which has seven full 
whorls, while michiganensis has but five. It agrees in all particulars 
with juvenile specimens collected with mature elodes. (See plate 
XXXIV, figures 17, 18, 19). It was at one time thought that michi- 
ganensis was the young of reflexa, but the receipt of adult specimens 
from the type locality shows conclusively that it is immature elodes. 
Elodes exhibits less variation, on the average, than does palustris. 
The internal varix of the outer lip is usually very heavy and the surface 
of the shell is frequently heavily malleated, a condition due to its char- 
acteristic habitat in ponds and streams which dry up in the summer. 
Galba elodes jolietensis (Baker). Plate XXXIV, figures 25-30; 
plate XXXV, figures 1-2. 
Limnea reflexa jolietensis BAKER, Nautilus, XV, p. 17, 1901; Moll. Chi. 
Area, II, p. 280, pl. 32, fig. 4, 1902. 
Lymnea reflexa jolietensis BAKER, Bull. Ill. State Lab. N. H., VII, p. 106, 
1906. 
Limnea reflexa attenuata Baxer, Trans. Acad. Sci. St. Louis, XI, p. 20, 
pl. 1, fig. 4, 1901 (non Say). 
