A MANUAL OF AMERICAN LAND SHELLS. 39 



Of the a.hove Polijgyra Jaclsoni and Zonites signijicans are included 

 with great hesitation. They are found at Fort Gibson, in Indian Terri- 

 tory.* They are more rehited to the fauna of the Cumberland Siibre- 

 gion than that of Texas. Triodopsis Levettei, a New Mexican species, is 

 also included. 



Besides the species characteristic of the North American fauna, which 

 Texas has, as xi portion of the Southern Kegion of the great Eastern 

 Province, we find in the above lists two species peculiar to it of the 

 characteristic American subgenus Mesodon — Uoemeri and direstnsA 



Several species on the list have been introduced from other regions, X 

 such as Strobila Hubbardl,^ a Jamaica species, as well as Macroceramus 

 Gossei, a Cuban species, which is also found on the Florida Keys; 

 Microphysa incruMata from Cuba, as well as PupapellueidaaudStenogyra 

 octonoides. 



Of the remaining species on the list, sixteen have actually been 

 found in Mexico ; probably all will be, as there seems no w^ell-defined 

 boundary here between the North American and Mexican fauna. 



Bulimulus serperastrtis, Say, although actually found in Texas, is evi- 

 dently a member of the Mexican fauna, and is therefore omitted from 

 my list, though included in the descriptive portion of my w^ork. 



The characteristic of Texas appears to be the great preponderance 

 of the genus Polygyra, of the type of F, Texasiana, while the type of 

 Florida, the septemvolva, is almost wanting. The great abundance of 

 individuals is also remarkable, showing the region to be peculiarly 

 adapted to pulmouate life. In the number of its species, also, the 

 Texas Kegion is favored ; by adding to the above list of peculiar 

 species those which it has in common with all of the Eastern Province, 

 and also those of the Southern Region, we find a total of seventy spe- 

 cies, the same number as found in Florida. 



On the map published in Terr. Moll. U. S., the Pacific Province, V, 



* See Terr. Moll. U. S., Vol. I, 122, -which gives the limits of the corresponding "South- 

 ern Interior Section"' such as would include these species. Several of the species 

 of East Tennessee also have been found in Arkansas— a fact also favoring a wider 

 limit to the Cumberland Subregion. 



t This species has not actually been found within the limits of the State of Texas, 

 but in the neighboring State of Arkansas and in Mississippi. To it may be applied 

 the remarks on Zonites significans and Polygyra Jaclsoni above. 



t Either by commerce, by oceanic currents, or from some former molluscous fauna 

 of which these now Isolated localities were offshoots. 



vS Since the above was written this species has been found- by Dr. Newcomb near 

 Savannah, Ga. It may therefore prove a widely distributed American species. In 

 Jamaica it is known as H. Vendreysiana, Gloyne. 



