VIII. 
OF THE DISTRIBUTION OF GENERA AND SPECIES IN THE 
UNITED STATES, COMPARED WITH THAT OF EUROPE 
AND SOUTH AMERICA. 
The distribution of the terrestrial mollusks in the 
United States, as compared with the temperate parts of 
Europe, presents some curious results. The following 
table shows the number of species found under the sev- 
eral genera ; 
GENEBA. 
NUMBER OF 
SPECIES. 
UiTKODUCED 
SPECIES. 
Vaginulus. 
Tebennophorui 
Arion. 
Limax. 
Vitrina. . 
Sucoinea. 
Bulimus. 
Helix. . 
Achatina. 
Glamlina. 
Pupa. 
Vertigo. . 
Cylindrella. 
Helicina. 
Cyclostoma. 
1 
2 
1 
3 
1 
8 
11 
71 
2 
2 
8 
5 
2 
3 
1 
1 

1 
2 
1 
1 
2 
5 
2 
1 
2 
1 
1 
1 
1 
Tutal 
Deduct introdu 
:ed s 
pecie 
s 
121 
22 
22 
Indigenous species. 
99 
