Weller — Kinderhook Faunal Shidies. 109 



three volutions ; the spire scarcely elevated above the body 

 volution, the suture very shallow, giving the upper side of the 

 shell a regular, gentle convexity. The last volution rapidly 

 expanding, the aperture oblique, oval, rounded posteriorly 

 and anteriorly, somewhat contracted on the inner side by the 

 rather broad inner lip. Height of shell, 11 mm., greatest dia- 

 meter, 16 mm., length of aperture, 11 mm., width of aperture 

 9 mm. 



Remarks. The fine, regular, elongate nodes mentioned 

 by Winchell as marking the upper ends of the striae of growth 

 on the outer volution, have not been observed upon either of 

 the two type specimens of the species in the University of 

 Michigan collection. 



Straparollus macromphalus Win. 



PI. Vl.f. 17-18. 



Shell of medium size, depressed, with a slighty elevated 

 spire and a broad umbilicus open to the apex of the spire; 

 volutions gradually enlarging, barely in contact, with a nearly 

 circular cross-section. Surface marked by regular lines of 

 growth. Diameter of shell, 21 mm., height, 9 mm. 



Remarks, In the type specimen of this species here illus- 

 trated, the spire is imperfectly preserved so that the number 

 of volutions cannot be accurately determined, but there are 

 probably not less than four and perhaps five volutions alto- 

 gether. 



Straparollus ammon (W. & W.). 



Fl. Vl.f. 22. 



Shell small, discoid, the spire not elevated above the plane 

 of the outer volution. Volutions three or four, closely coiled, 

 gradually enlarging from the apex, slightly angular on the 

 upper side, rounded below, and on the back. Umbilicus very 

 broad, exposing nearly the whole of the inner volutions. 

 Surface of the shell marked by fine, closely arranged trans- 

 verse striae of growth, which have a gentle backward curva- 

 ture from the suture line to the under side of the volution. 



Remarks. The actual type specimen of this species was 

 not found in the University of Michigan collection, but an- 



