4S2 PROCEEDINGS OF THE ACADEMY OF [July, 



ectocones. They are of the aculeate rather than the quadrate form. 

 Further out the cusps are strictly aculeate, but short and stout. 



Binney records 19, 1, 19 and 17, 1, 17 teeth in specimens of laevigata 

 he examined. His figure shows rudimentary side cusps, but no 

 cutting points on the central, and a well-developed ectocone on the 

 first lateral tooth. The locality of his specimen is not stated. 



Mesomphix laevigata perlaevis (Pils.). 



Omphalina laevigata perlcevis Pilsbry, Proc. A. N. S. Phila., 1900, p. 135. 

 Ferriss, Nautilus, XIV, p. 56. 



(a) The radial strise on the embryonic 1-| whorls are coarser than 

 in kevigatus, weak or wanting on the first half whorl. The typical 

 form from Tallassee Ford, Monroe County, Tenn., has irregular 

 wrinkles on the last whorl, with a spiral sculpture of very faint, 

 close, smooth lines, often nearly or quite obsolete. The largest 

 shell of the type lot measures: alt. 10, diam. 17.5, aperture alt. 9, 

 width 10 mm. ; whorls 4|. 



A few shells, not quite adult, from Lawrenceburg, Dearborn 

 County, Ind. (A. C. Billups), do not appear to differ from perlcevis. 



(6) Three lots from Macon County, Ga., and Black Mountains, 

 N. C, collected by Hemphill, and from Burnside, Ky., collected 

 by Ferriss, differ by having the last whorl closely striate above, but 

 under the microscope only very fine, smooth, spiral lines are seen. 

 A specimen from Macon County measures: alt. 12, diam. 19.5, 

 aperture 9x11 mm., with 5 whorls. 



(c) Another form related to perlcevis is densely striate above, but 

 the aperture is wider, less rounded. The upper surface is often 

 russet-tinted, as in M. kevigata, but the microscopic spirals are 

 faint, fine and smooth, not granulose. The aperture is more oblique 

 than in the preceding race. Alt. 12, diam. 21, aperture 9.3 x 12.7 

 mm., whorls 5. 



This form is from Cheoah River at the junction of Yellow Creek, 

 Graham County, N. C. 



Some shells not quite mature, but apparently the same, were 

 taken by Rhoads at Sawyer Spring, Walden's Ridge, Hamilton 

 County, Tenn., at an elevation of about 2,300 feet. 



Forms (b) and (c) may eventually be separated as distinct sub- 

 species. 



Mesomphix laevigata latior Pils. 



Omphalina kevigata latior Pils., Proc. A. N. S. Phila. 1900, p. 135. Ferriss, 

 Nautilus, XIV, p. 56. 



The sculpture of the embryonic 1| whorls is coarser than in 



