354 The American Geologist. December, i90i 
no case, however, are they generally distributed in the loess, 
and with the possible exception of Limnaea caperata and L. 
hunhilis, very few individuals are found. In order that the 
comparative scantiness of the fossil aquatic molluscan fauna 
may be more fully appreciated a list of the local aquatic species 
is here given. Those which also occur in the local loess are 
marked by two asterisks, and those which are positively known 
as fossils only from other localities are marked by one asterisk. 
2. ^'iOUATIC SPECIES NOW LIVING AT loWA CiTY. 
a. Species of smaller ponds, etc., which often become 
dry in summer. 
*LlMNAEA REFLEXA Say. 
Common some years in shallow ponds. Not found in the 
loess of Iowa and Nebraska, but reported from Missouri by 
Hambach.* 
**LlMNAEA CAPERATA Say. 
Locally very common. As a fossil it occurs in but fev/ 
exposures, and in these is usually restricted tc narrow bands 
or pockets, in which it is quite abundant. 
**LiMNAEA HUMiLis Say. 
Very common in shallow ponds, or on mud-flats. As a fos- 
sil it occurs with the preceding species, and is even more com- 
mon. 
*-'=LlMNAEA DESIDIOSA Say {?). 
Some of the smaller fossil shells of Limnaea may belong 
to this species. It is probably foiuid in the loess westward, 
though in some cases at least the fossils reported under this 
name undoubtedly belong to the preceding species. Common 
in shallow ponds. 
**Physa gyrina Say. 
Very Common in shalllow ponds. Two very small speci- 
mens, probably this species, were found in the loess at Iowa 
City. 
PhYSA INTEGRA //a/cl 
Very common in ponds, etc. Hitherto reported as P. 
heterostropha Say. In a very large series of shells from 
Iowa and Nebraska not one specimen of the latter species 
was found. 
*Geo]. Sur. of Mo., Bull. No. 1, p. S2, April, 1890. 
