320 THE CHICAGO ACADEMY OF SCIENCES. 



Animal: See under P. subulare. 



Distribution: Ohio, Tennessee, Alabama, Illinois, Indiana, 

 etc. 



KEY TO SPECIES OF PLEUROCERA. 



a. Last whorl rounded or subangulated; whorls rounded; aper- 



ture oval , subulare 



b. Last whorl strongly carinated, whorls flat-sided, often heav- 



ily spirally striated; aperture triangular elevatum 



130. Pleurocera subulare Lea, pi. xxxv, figs. 1, 2. 



Melania subularis LEA, Trans. Amer. Phil. Soc., Vol. IV, p. 100, pi. xv, 

 fig. 30, 1834. 



Shell: Smooth, elevated, acute, turreted; color pale brown- 

 ish horn, with a yellowish band encircling the whorls just below 

 the suture; there is sometimes an indication of a purplish band 

 just above the periphery; apex rounded, smooth, horn-colored, 

 bent in toward the whorls; surface shining, polished, lines of 

 growth oblique, crowded, here and there more elevated than 

 the average; sutures deeply impressed; whorls eleven, regu- 



FIG. 114. 

 Operculum of PLEUROCERA SUBULARE Lea. (Original.) 



larly increasing, the upper seven carinated just above the su- 

 ture, the last four rounded; base of shell broadly conic, suban- 

 gulated; imperforate; aperture ovate, narrowed above, white 

 or bluish-white within, sometimes showing two spiral, brownish 

 bands, produced and somewhat canaliculate below; peristome 

 acute, sinuous, rather thick; columella bluish-white, twisted; 

 terminations of peristome and columella joined by a thick, 

 somewhat spreading callus. Operculum paucispiral, chestnut 

 brown, the nucleus on the lower margin of the left side. The 

 lines of growth rather coarse, showing under a lens that the 

 operculum is made up of small plates or laminae (Fig. 114). 

 Length, 22.00; width, 8.00; aperture length, 6.50; width, 4.00 mill. (9967.) 

 21.00; " 7.00; " " 7.00; " 3.50 " (9967.) 



24.00; " 8.00; " " 7.00; " 4.00 " (9967.) 



18.00; " 7.50; " " 7.00; " 4.00 " (9967.) 



20.50; " 7.50; " " 7.00; " 4.25 " (9967.) 



Animal: With a wide, short, thick foot, truncated before 

 and rounded behind; color blackish above, yellowish under- 



