340 THE CHICAGO ACADEMY OF SCIENCES. 
Remarks: efleva is one of the commonest of the Lymnzas in 
certain localities ; it is very variable and is frequently confounded with 
long-spired specimens of Galba clodes. The spire of reflexa 1s always 
longer than the aperture, and may be twice as long. As a general rule, 
reflexa has higher whorls in comparison with their width than in 
elodes; the last two whorls are disproportionatcly larger and the pe- 
nultimate whorl is usually large and has a “puffy” appearance (in 
clodes they usually taper gradually and regularly to a point); the 
whorls are also roynder, with deeper sutures. Moreover, reflexa is 
very rarely malleated, while elodes usually shows traces of malleation 
due to its wallowing habit. The aperture in reffe.ra is also more half- 
moon-shaped and has a peculiar “twist.” A close study of the shape 
of the whorls will almost invariably separate reflera from elodes. 
Failure to note these points has caused some authors to assert that 
reflexa runs into palustris (elodes), but a study of abundant material 
does not bear out this statement ; young specimens of refleva and elodes 
resemble each other, the parallel between them being the same as be- 
tween immature Polygyra thyroides and P. albolabris. Even half- 
grown specimens of clodes can be distinguished from reflexra by the 
shape of the body whorl, which in the latter species is more com- 
pressed and flattened than in clodes. The majority of specimens of 
reficra examined have been usually constant in form. The inner lip 
is sometimes raised so as to make the aperture continuous (pl. XXXV, 
fig. 15), and the epidermis is sometimes heavily zebra-marked, both 
spirally and longitudinally. The spire varies somewhat in height. 
Very old individuals which have survived until the third season are 
exceptionally large and the aperture is peculiarly oblique and reflexed. 
CPLESXXO XV, fig. 8b) 
Say’s types of reflevxa (two specimens) are still preserved in the 
Academy of Natural Sciences of Philadelphia (No. 58639). The shells 
consist of 614 whorls, which are rounded and not flat-sided as in Say’s 
figure published in Binney, but more like Say’s figure in the American 
Conchology. (See plate XXX, figures 30, 31.) Haldeman’s plate 8 
is typical of the majority of specimens referred to reflexa. Crystal- 
ensis (plate XXXVI, figures 7-11) is the immature state of reflea, 
a fact recently demonstrated by an ecological study of certain summer- 
dry ponds or “swales” in northern Illinois. Both forms may be found 
associated together, the fully mature reflera being a crystalensis of 
the third year. This immature form resembles elodes, from which it 
may be distinguished by its more tightly coiled upper whorls, its nar- 
rower aperture and more cylindrical whorls. 
