GEOGRAPHICAL DISTRIBUTION. 



35 



Sub-Region have spread into its northern portion, and the following 

 have extended over the larger portion of it : — 



Macrocyclis concava. 

 Zonites fuliginosus. 



inornatus. 



suppressus. 



iudentatus. 



arboreus. 



minusculua. 

 Limax campestris. 

 Patula alternata. 

 Helicodiscus lineatus. 

 Strobila labyrinthica. 

 Stenotrema hirsutum. 

 monodon. 

 Triodopsis palliata. 



tridentata. 

 fallax. 



Triodopsis Van Nostrandi. 

 Mesodon albolabris. 

 thyroides. 

 Pupa pentodon. 



fallax. 



armifera. 



contracta. 



rupicola. 



corticaria. 

 Vertigo milium. 



ovata. 

 Succinea avara. 



obilqua. 

 Tebennophorus Caroliniensis. 

 Pallifera dorsalis. 



Equally wide over the Region has been the distribution of those 

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

 p. 26). Such are: Zonites viridulus, ftdvus, 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, in the peninsula of Florida, from whence, indeed, many of them 

 have not yet spread over the whole Region : — 



Glandina truncata. 

 Zonites cerinoideus. 

 Polygyra auriculata. 



uvulifera. 



Postelliana. 



espiloca. 



avara. 



cereolus. 



septemvolva. 



Carpenteriana. 



Febigeri. 



pustula. 



pustuloides. 

 Triodopsis Hopetonensis. 



Of the more widely spread species, Polygyra septemvolva is represented 

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

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



Mesodon major, 

 jejuna. 

 Mobiliana. 

 Bulimulus Floridanus. 

 Dormani. 

 dealbatus. 

 Cylindrella jejuna. 

 Pupa variolosa. 



modica. 

 Succinea effusa. 



campestris. 

 Wilsoni. 

 Veronicella Floridana. 



