108 MANUAL OF THE MOLLUSCA. 
Carolinensis, and Unio complanatus and radiatus, are character- 
istic of the eastern rivers; Melania depygis is said to be the 
only member of that large genus found eastward of the Hudson 
River. Of the American land-snails, 29 sp. of Helix, 6 Suc- 
cineas, and 13 Pupas are enumerated from the Atlantic States. 
In Florida the propinquity of the West Indian fauna is strongly 
indicated by the occurrence of the great Glandina truncata, by 
species of Cylindrella, and a Helicina. A Cuban species of 
Chondropoma (C. dentatum) is also said to occur in Florida, and 
Ampullaria depressa in Florida and Georgia. 
The Pulmonifera of North America have been carefully exa- 
mined by Messrs. Binney,* Bland,+ and others. The following 
summary of North American Pulmoniferais given by Mr. Binney, 
The area is nearly co-extensive with our regions, Nos. 16 
and 17. 
DATION Rees ncccascvietss ares 2 ABUTS! 2, sree ocdeceaence 21 Melampus .....-..cs-0--6 11 
WAAR cee S acceso se <ae 3 ANG TRINENE) \Sacascppacoenos 5 Cary chim css.ce--5 1 
PHWOMY CUS) c..0<00 00500 2 PUPG aerestincasesscseeaee 12 TAMONA: ss .se0cseneseenee 34 
WVAITANS ees. ccsstovescese 2 IVETE GON sue. se sce sserece 4 SPY Saeecee ee aeeeeeeneeeee 19 
TICCINED ob scdevsecceeres 18 Cylindrella ............ 4 PlanOrbis ..cccnssessszee 21 
Gandia) o.csece~ss0 sce: 6 WELOnIGeIH A) fesesccerees 1 ATIGYMUS: 2280 «se asenseeene 10 
AGU So seu sees secee 131 
There are also found in the fresh waters of this district J/ela- 
niade 380, Paludinide 58, Cycladide 44, Unionidee 552. 
18. AMERICAN REGION. 
The mass of American land and fresh-water shells are found 
in the central and southern States, the country drained by the 
Mississippi and its tributaries. The Helicide are not more re- 
markable for size and colour than those of northern Europe ; 
the most characteristic forms belong to the sub-genus Polygyra 
(or Tridopsis, Raf.), such as Helix tridentata, albolabris, hirsuta, 
and septemvolvis. The truly North American forms all belong 
to three genera, viz.—Helix 43, Succinea 8, Pupa 3 species. 
In the Southern States are also found 5 species of Bulimus, 
3 Cylindrellas, 2 Glandinas, and 5 Helicine, genera whose 
metropolis is in the Antilles or in tropical America. 
The fresh-water univalyes include above 100 species of Mela- 
niade belonging to the genera Ceriphasia, Melafusus, Anculotus, 
Melatoma, and Amnicola, 15 Paludine, some keeled, and one 
* Tn several papers in Proc. Acad. Nat. Sci. Phil. 1°57, and subsequent years, 
+ Remarks on the Classification of N. Am. Helices Annals of Lyceum of Nat. Hist, 
New York. 1363. 
