GEOGRAPHICAL DISTRIBUTION. H<;i 
of its most southern portion, including the islands of the 
coast, has demonstrated that many of the land-mollusks 
indigenous to Cuba, are found both on the main land and 
the islands, and that others which are derived from a more 
distant source, also exist there. Among the former are 
Pupa incana, Oylwdrella lactaria, Cyclostoma dentatum, 
Bidimus undatus and fasdatus; and among the latter, 
Bidimus virgidatus, and Helix rhodocMla, selenina, 
ottonis, &c. There are other species which, so far as is 
at present ascertained, are peculiar to this section. Such 
is Vaginidus floridanus. Dead and worn specimens of 
other Cuban species are also sometimes seen in collec- 
tions, and represented to have been procured in Florida, 
but the evidence that they actually were, is not entirely 
satisfactory. The other species indigenous to this sec- 
tion are the same which are found in the next northern 
section. The influence of a mild climate approaching 
that of the intertropical regions, and very favorable to 
the multiplication of species, is counteracted, in some 
degree, by the excessive humidity of large tracts, and 
by the general prevalence of a sandy soil. For this 
reason, though in some situations they exist in multitudes, 
there are extensive portions where it is almost impossible 
to discover a single one ; and, in general, it may be said, 
that individuals are multiplied whilst species are re- 
strained. The marked characteristics of this section, 
and its near approach to a tropical climate, lead us to 
expect that when it shall have been thoroughly explored 
it will be found to contain more than the twenty-eight 
