VIVIPARA. 13 
and have not the facilities for observing the 
animal in action, can satisfy themselves by a 
comparison of Haldeman’s figure of Paludina 
decisa at rest (Plate I, fig. 1) with Mr. Bin- 
ney’s figures above cited. 
Thus, then, I divide Vivipara: 
* Whorls regularly rounded, generally banded, 
texture thin, umbilicate. typical. 
Inhabits all parts of the world. The Ameri- 
can species very evidently belonging to the 
European group. 
** Whorls flattened around their upper por- 
tions, generally without bands, solid, 
nearly or quite imperforate. 
A group peculiar to North America. 
Smooth. Subgenus Melantho. 
g 
+t Nodulous. eh Tulotoma. 
The following species belong to each group ; 
those described by Haldeman being in Roman 
type, spaced, and the species characterized 
more recently in italic : 
Vivipara,intertexta, Say, vivipa 
[89] 
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