22 



cellated appearance ; while they are closer and finer on the 

 lower side of the shell ; mouth transversely oval ; umbili- 

 cus small. 



Diameter *10 to *19 ; height *07 to *14 of an inch. 

 Locality. — Bloomington ; Spergen Hill, Indiana. 



IS Pleurotomaria Meekana.-- Shell depressed-conical; spire 

 short, rapidly diminishing and obtuse at the apex ; volutions 

 about five, appressed above and sub-angular below, with 

 the periphery vertical ; suture distinct ; last volution large, 

 not ventricose, biangular on the periphery, with a defined 

 groove in the centre which is distinctly margined above 

 and below by an elevated line ; surface on the upper 

 side of the volutions marked by revolving and transverse 

 striae of equal strength, which are regularly cancellated, 

 (and when not worn there is a slight nodosity at the cross- 

 ing). The revolving lines on the base of the last volution 

 are closer and finer than those above, and equally, but less 

 distinctly, crossed by the transverse lines which make a deep 

 sinuosity on the the periphery of the shell. Aperture sub- 

 quadrate with a deep notch in the outer margin at the ter- 

 mination of the revolving band ; umbilicus of medium size. 



Diameter *18 ; height *13 of an inch. 



Locality. — Spergen Hill. 



Pleurotomaria Piasaensis. — Shell depressed, sub-glo- 

 bose ; spire short and little elevated, consisting of about 

 four volutions; volutions rapidly increasing in size, depres- 

 sed-convex above, somewhat rounded below, and becoming 

 sub-angular near the aperture ; the periphery abruptly 

 rounded and marked by a spiral groove or band ; surface 

 marked by about four strong spiral or revolving strige on the 

 upper side of the volution, between the periphery and su- 

 ture, and four or five similar strise on the lower side ; trans- 

 verse strise scarcely distinct except in the spaces between 

 the revolving strise ; umbilical depression rather broad, and 

 margined by a strong angular elevation towards the aper- 



