68 LAND AND FRESIl-WAXER SHELLS OF N. A. [I'ART IIL 



Yerge (iu B. ferrusina) bifid. Sliell elongated-ovate, usually 

 somewhat pupiform, imperforate, or simply rimate ; apex obtuse. 

 Aperture oval or rouuded ; peritreme coutinuous, slightly thick- 

 ened. Operculum corneous, with the nucleus moderately large, 

 not very close to the basal margin. 



Station, fresh water. 



Distribution, Europe and Nor.th America. (Stivipson.) 



Bytliinella attenuata, Hald. — Shell unusually long, slender, 

 with G or 7 obliquely revolving, very convex whirls, separated by a deep 

 suture ; aperture small, ovate, with the peritreme level and 

 Fig. 132. coutinuous ; labium in contact with the body whirl, leaving 

 scarcely any perforation. 

 A Color pale-green beneath an extraneous coating of black. 



r~) Taken from a spring in Montgomery County, Virginia, 



^"'^ connected with Roanoke River. 



Bytliinella I ^°i ^ot confident that this is not the adult of nicliniana, 



attenuata. as there is a very close resemblance between that shell and 

 the young of this species, when it has but foUr volutions. 

 In the latter, the aperture appears to be rather contracted. {Haldtman.) 



Amnicola attenuata, Haldeman, Mon. pt. 4, p. 3 of wrapper (1842) ; Ib. 



Mon. p. 22, pi. i, f. 13 (1844?) ; Ib. Jouru. Acad. N. Sc. Phila. VIII, 



200 (1842) ; Ib. Proc. I, 78 (1841). 

 Amnicola elongata, Haldeman, /. c. in plate. 



It is also said to inhabit New York. Amnicola elongata, Jay, 

 of the Smithsonian Check Lists, is probably this species. No 

 synonymy or reference is given by Dr. Jay (Cat., p. 27 8). 



Bytliinella nickliiiiaiia, Lea. — Shell turreted, green, smooth ; 

 apex obtuse ; whirls 4, convex ; aperture 

 Fig. 133. ovate. Hot Springs, Va, Diam. two- 'Fir. 134. 



twentieths ; length three-twentieths inch. 



This shell, with several other species, J^ 



was brought by Mr. Nicklin from the Hot (^\ 



Springs of Virginia, and kindly placed ^J/ 



in my cabinet. It lives in a rivulet, BythinelUi 

 whose channel is supplied by the waters nicklmiana. 

 of a hot and a cold spring. The Physa 

 aurea inhabits the same stream. It is the smallest species I know in our 

 country, except the aranosa of Say. It is rather larger, and very much re- 

 sembles the riridis Lam. Its habitat, however, is very different, as the 

 firidis lives in cold fountains. (Lea.) 



