110 Trans. Acad. Set. of St. Louis. 



1902. Baker, Frank C. Mollusca of the Chicago Area. 



Part II, p. 290, pi. XXX, fig. 28. 



1903. Walker, Bryant and Lane, A. C. Kecent Shells of 



the Marl. Geological Survey of Michigan, vol. VII, 

 pt. ii, p. 251. 



Issued May 11,1904. 



