36 



A MANUAL OF AMERICAN LAND SHELLS, 



Mesodon thyroides. 

 Pupa pentodo7i. 



fallax. 



armifera. 



contracta. 



rupicola. 



corticaria. 



Vertigo milium. 



ovata. 

 8uccinea avara. 



ohliqua. 

 Tebennophorus Caroliniensis. 

 dorsalis. 



Equally wide over the region has been the distribution of those 

 minute species whose origin has been traced to circumpolar regions (see 

 p. 27). Such are: Zonites viridtilus, fulviis, and Vallonia pulchella. 



In addition to these species derived from the north are found the fol- 

 lowing species peculiar to the region, whose origin can be traced to the 

 south, iu the peninsula of Florida, from whence, indeed, many of them 

 have not yet spread over the whole region : 



Olandina truncata. 

 Zonites cerinoideus. 

 Polygyra auriculata. 



uvulifera. 



Postelliana. 



espiloca. 



avara. 



cereolus. 



septemvolva. 



Carpenter iana. 



Febigeri. 



pustula. 



pustuloides. 



Mesodon major, 

 jejunus. 

 Mobiliarins. 

 Bulimuhis Floridanus. 

 Dormani. 

 dealbatus. 

 Cylindrella jejuna. 

 Pupa variolosa. 



modica, 

 Succinea effusa. 



campestris. 

 WilsonL 

 Veronicella Floridana. 



Triodopsis Hopetonensis. 



Of the more widely spread species, Polygyra septemvolim isrepresented 

 by various forms over the whole southern littoral region, both of the 

 Atlantic and Gulf. So is Glandina truncata, Mesodon jejunus, Polygyra 

 pustula, pustuloides, and Pupa modica. Triodojysis Hopetonensis extends 

 only along the Atlantic alluvial region. Bulimulus dealbatus is also 

 distributed over the whole region, from IN'orth Carolina to Texas, and 

 has spread northward to Arkansas and Kentuck3\ Succinea campestris 

 extends along the Atlantic coast as far as South Carolina, as does also 

 Zonites cerinoideus, even into North Carolina and Virginia. Polygyra 

 espiloca and Postelliana have been noticed thus far in the southeastern 

 corner of Georgia. The former also at New Orleans and ludianola. 



