THE NAUTILUS. 19 



ered \vitli ;i spreading callus ; the lower part of the aperture is 

 somewhat produced. 



'Length -22.00; width 13.50 ; aperture length 10.00; width 7.50 

 mill. (Chicago.) 



Length UKOO ; width 12.00; aperture length 14.00; \\idthG.OO 

 mill. (Chicago.) 



Length 1000; width 11.00; aperture length 12.00; width 6.00 

 mill. (Chicago.) 



Animal similar in external appearance to all Physidae. Jaw and 

 radula as in yyriiia. Distribution: Ohio, Indiana, Michigan, Illi- 

 nois, Missouri. Geological distribution : Pleistocene ; Loess. Habi- 

 tat : In stations similar to heterostropha and gyrina. 



Remarks: This species was at first identical as ancillaria Say, 

 but that species, while having the same surface sculpture as sayii, is 

 more inflated, the outer lip more spreading and the body whorl more 

 gibbous, the spire being always much shorter and the whorls more 

 convex. The surface sculpture is very beautiful and precisely as de- 

 scribed for yyrina. This species is not common, and has been found 

 at Joliet, Maywood. Lake Calumet and Lake Michigan near the foot 

 of Oak Street. Sayii is apparently closely related to ampullacea 

 Gould, a Pacific coast species. 



Physa gyrina Say. Fig. 3. 



Physa gyrina SAY, Journ. Acad. Nat. Sci. Phil., vol. 2, p. 171, 

 1821. Physa striata MENKK, Syn. Math., ed. 2, p. 32, 1830. 

 Physa hildrethiana LEA, Proc. Amer. Phil. Soc., vol. 2, p. 32, 1841. 

 Physa cyllndnca NEWCOMB, in DeKay, N. Y. Moll., p. 77, pi. V, 

 fig. 82, 1843. Physa plicata DEKAY, 1. c., p. 78, pi. V, fig. 85, 

 1843. P/tysa sajf'ordii LEA, Proc. Phil. Acad. Sci., p. 115, 18G4. 

 Physa haw nii LEA, 1. c., p. 115, 1864. Physa parva LEA, 1. c., 

 p. 115, 1864. 



Shell elongated, generally polished, whorls 5-6; spire always very 

 long (as compared with the last two species), acute, the whorls in 

 some cases almost flat, and at best but slightly convex, color varying 

 between light-greenish horn and brick-red ; sculpture consisting of 

 well-marked growth lines, crossed by numerous fine impressed spiral 

 lines, giving the shell a wrinkled appearance (see figure of sculp- 

 ture) ; these lines appear at first to be raised, but when viewed 

 through the microscope are seen to be impressed between two wrin- 

 kled ridges, as seen in the cut ; sutures scarcely impressed, but 



