202 Trans. Acad. Sci. of St. Louis. 



Capulus vomerium (Win.). 



PL XX. f.l5. 



Original description. *' Shell of medium size, describing 

 about half a direct whorl, very rapidly enlarging ; peripheral 

 (or dorsal) region elevated and surmounted by a strong, 

 broad, rounded carina, which becomes more obtuse toward 

 the aperture, — a shallow groove running along each side of 

 the carina; transverse section showing an angle of about 70° 

 toward the beak, which enlarges to about 110° near the aper- 

 ture; surface of cast destitute of markings." 



** Distance from front of aperture in a straight line, to most 

 projecting portion of beak 21 mm., height of shell when 

 resting on aperture 12 mm., summit when in this position 

 three-fifths the distance from aperture to apex, length of 

 aperture 17 mm., width of aperture 15 mm." 



Remarks. The type of this species has not been seen, but 

 the individual illustrated is an authentic specimen in the 

 University of Michigan collection labeled by the author of the 

 species. It differs from the type chiefly in being much 

 smaller. The species can be easily recognized by its strongly 

 carinate periphery. 



Igoceras undata (Win.). 

 PI. XX. f. 16. 

 Metoptoma undata^ Bull. U. S. G. S. 153 : 351. 



Original description. '* Shell of medium size, nearly erect, 

 apex nearly central, aperture transversely slightly elliptic; 

 body of shell most inflated in the middle, somewhat acumi- 

 nate toward the apex, and contracted at the aperture. Cast 

 nearly smooth over the body of the shell, longitudinally un- 

 dulate near and at the aperture, with a few wavy concentric 

 lines of increment." 



*' Height of shell 29 mm., longest diameter of aperture 

 27 mm." 



Remarks. With the original description of the species it 

 is said to be from '* bed No. 5." but this must be a mistake, 

 since the lithologic character of the type specimen shows 

 conclusively that it is from the magnesian limestone bed. 

 The species has not heretofore been referred to the genus 

 Igocerus, but if that group of Capulid shells is really deserv- 

 ing of generic rank this species is certainly a member of thegenus. 



