338 TRANSACTIONS OF THE WAGNER FREE 



Grand Gulf beds at Vernal, Green County, Miss., in October, 1889, by Mr. 

 L. C. Johnson, of the U. S. Geological Survey. The depth at which the same 

 bed was found near the coast at Mobile indicates a seaward dip of about 

 twenty-five feet to the mile, which is in accordance with the result deduced 

 from observations on other beds in the same general region by Hilgard, Smith 

 and other geologists. 



Genus BYTHINELLA Moquin Tandon. 



Bythinella Nickliniana Lea, var. attenuata Haldeman. 



Plate 21, figure 19. 



Paludina Nickliniana Lea, Trans. Am. Phil. Soc. vi. p. 92, pi. xxiii. fig. 109, 1839. 

 Bythinella Nickliniana Binney, L. and F. W. Sli. N. Am., part 3, p. 68, fig. 134, 1865. 

 Amnicola attenuata Haldeman, Wrapper of Mon., part 4, p. 3, 1842 ; Mon., p. 22, pi. i. fig. 



13, 1844- 

 Annicola elongata Haldeman, op. cit. on plate. 

 Bythinella attenuata Binney, op. cit. p. 68, fig. 132, 1S65. 



Pliocene of the Caloosahatchie beds and Shell Creek, Florida, Dall and 

 Willcox ; living in the fresh-water streams of Virginia, Pennsylvania and New 

 York, and probably most of the Southeastern States. 



The specimen figured is of the elongate variety, but others found varied 

 from that to the typical Nickliniana, so that there can be no doubt Mr. Pils- 

 bry is quite justified in uniting the two under one species. 



Genus AMNICOLA Gould and Haldeman. 



Amnicola floridana Frauenfeld, var. convexa Pilsbry. 



Amnicola floridana Frauenfeld, Verb. K. K. Zool. Bot. Ges., Wien, April, 1863, p. 1028, 

 and 1865, p. 529, pi. X. fig. 4, a-b. 



Pliocene marls of the Caloosahatchie and Shell Creek, Florida, Dall and 

 Willcox ; living in the fresh waters of Florida at the present time. 



" Shell turbinate-conic, with narrow conical .spire, rather obtuse apex, 

 and deep sutures; whorls nearly five, very convex, lightly marked with irreg- 

 ular incremental lines, aperture ovate, slightly narrower behind, but not 

 angular; peristome continuous, the outer lip often somewhat expanded ; the 

 inner lip less curved than the outer one, and either free or in contact with the 

 body-whorl above ; umbilicus large and conspicuous. Several specimens 

 give the following measurements : Alt. 3.5-3.5; diam. 2.3-2.4; alt. of aper- 

 ture 1.4-1.7 mm. 



" Differs markedly from A. floridana in the narrow spire, deep sutures, 

 wider umbilicus, and less attached peristome ; but as the specimens are very 

 variable, and as the differential characters mentioned are precisely those com- 

 monly found in degenerate Amnicolidce the world over, not much dependence 

 can be placed upon them. " [H. A. P.] 



