36 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



pustula, pustuloides, and Pupa modica. Triodopsis Hopetonensis ex- 

 tends only along the Atlantic alluvial Region. Bulimulus dealbatus 

 is also distributed over the whole Region, from North Carolina to 

 Texas, and has spread northward to Arkansas and Kentucky. Suc- 

 cinea campestris extends along the Atlantic coast as far as South Caro- 

 lina, as does also Zonltes cerinoideus, even into North Carolina and 

 Virginia. Polygyra espiloca and PosteUiana have been noticed thus far 

 in the southeastern corner of Georgia. The former also at New Orleans 

 and Indianola. Succinea Wilsoni, at Darien, Ga. Mesodon major ex- 

 tends from the Gulf to Abbeville, S. C., confined to a narrow track of 

 territory. 



The following European species have been introduced by commerce 

 into this Region, and still exist at the points named : Stenogyra decol- 

 lata, Lin., Turricula terrestris and Pomatia as2)ersa, Mull., at Charleston, 

 S. C.'; Ccecilianella acicula, Miill., Florida. 



From the list of species peculiar to the Southern Region it will be 

 seen that the prevailing form is Polygyra, a group or genus peculiarly 

 American, represented in the Interior Region indeed, but meeting its 

 greatest development here. The presence of Glandina and Veronicella 

 shows, also, the more southern character of land-shell fauna. But the 

 Region, and especially that portion of it from whence the fauna was 

 ^distributed, i. e. the southern extremity of Florida, is still more peculiar 

 in showing the connection between the land shells of the continent of 

 North America and those of the West India Islands and the Spanish 

 Main. Of the species given above (p. 35), Cylindrella jejuna was, per- 

 haps, introduced from Cuba, and Bulimulus Dormant may prove iden- 

 tical with B. maculatus, Lea, of Carthagena. The following species have 

 evidently been introduced 1 from the West India fauna : 2 



Zonites Gundlachi, Cuba, etc. Bulimulus Marielinus, Cuba. 



Patula vortex, Cuba, etc. Strophia incana, Cuba. 



Hemitrochus varians, New Providence. Stenogyra subula, Cuba, etc. 

 Cylindrella Poeyana, Cuba. gracillima, Cuba, etc. 



Macroceramus Kieneri, Cuba. Liguus fasciatus, Cuba. 



Gossei, Cuba. Orthalicus undatus, Cuba. 



From Yucatan one species has been introduced, Polygyra oppilata. 



1 Either by oceanic currents since the formation of the peninsula of Florida, or else 

 from some island of the West India group, now enclosed in the peninsula. It is interest- 

 ing in this connection to refer to the discovery, by Mr. Conrad, of a Tertiary fossil at 

 Tampa Bay, Bidimus Floridanus, Conr. See also below, p. 40. 



3 Also several non-pulmonate species, as Helicina subglobulosa, Cuba ; Ctennpoma 

 ruffulosum, Cuba ; Chondwpoma dentatum, Cuba. 



