30 University of Michigan 



out entirely as insufftciently defined, there seems little reason 

 for reconsidering Lea's restriction, which has been accepted 

 for three-fourths of a century." (H. A. P.) 



Eluptio dilatatus (Rafinesque), 1820 

 Type locality: Ohio River. 



Unio dilatata Rafinesque, '20, p. 297. 



Unio gibbosus Barnes, '23, p. 262, pi. 11, f. 12. 



U. dilatatus Raf. = C7. gijbbosus Bar., Conrad, '34, p. 68; Ferussac, 

 '35. P- 27; Conrad, '36, p. 42, pi. 21. 



Unio gibbosus Bar., Simpson, '14, p. 597. 



U. dilatata Raf. =: Obliquaria si'Hiata Raf. = U. gibbosus Bar., Van- 

 atta, '15, p. 555 ("types" examined). 



U. dilatata Raf. = (/. gibbosus Bar.. Walker, 'i6fi, p. 46 and iS"", 

 p. 175 ("if identifiable"). 



Elliptic dilatatus (Raf.), Utterback, '16, p 90; Ortmann, '18, p. 556. 



The original description of dilatata Raf. indicates a long, 

 elliptical, posteriorly somewhat attenuated, brownish shell, 

 with violet nacre. This can be only one species of the Ohio, 

 the gibbosus Bar., and the latter name has to give way to 

 dilatatus. 



Eluptio complanatus (Dillwyn), 1817 



Type locality: Maryland and New Jersey. 



For this well-known species Haas (Vid. Middel, Dansk 

 Naturh. Foren., LXV, 1913, p. 54) has revived the name of 

 Unio violaceus Spengler (1793), relying on the identification 

 of the type. However, Walker ('I8^ p. 3) has shown that 

 this name cannot be used, since the original description of 

 znolaceus is entirely insufficient to recognize the species. "More- 

 over, the species had been named Mya complanata in the Port- 

 land Catalogue, 1786, p. 100." (H. A. P.) 



Elliptio productus (Conrad), 1836 

 Type locality: Savannah River, Augusta, Ga. 

 Obliquaria cuprea Rafinesque, '20, p. 304, pi. 81, f. 8-9. 



