lymn^eim: 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. 



Limncea reflexa jolietensis Baker, Nautilus, XV, p. 17, 1901; Moll. Chi. 

 Area, II, p. 280, pi. 32, fig. 4, 1902. 



Lymncea reflexa jolietensis Baker, Bull. 111. State Lab. N. H., VII, p. 106, 

 1906. 



Limncea reflexa attenuata Baker, Trans. Acad. Sci. St. Louis, XI, p. 20, 

 pi. 1, fig. 4, 1901 (non Say). 



