1 8 University af Michigan 



QuADRULA VERRUCOSA (Rafinesque), 1820 

 Type locality: Ohio River. 



Obliqtuiria verrucosa Rafinesque, '20, p. 304, pi. 81, f. 10-12. 



Unio tuberculatus Barnes, '23, p. 125, pi. 7, f. 8. 



U. verrucosus Raf. = U. tuberculatus Bar., Conrad, '34, p. 72; Ferus- 

 sac, '35, p. 27. 



Tritogonia tuberculata (Bar.), Simpson, '00^, p. 608; '14, p. 318. 



Trit. verrucosa {Rai.)=Trit. tuberculata (Bar.), Vanatta, '15, p. 

 554 ("types" examined). 



Obi. verrucosa (Raf.) =:Trit. tuberculata (Bar.), Walker, '16^, p. 45, 

 and 'i8c, p. 170 ("if identifiable"). 



Quad, verrucosa (Raf.), Utterback, '16, p. 62; Ortmann, '18, p. 540. 



Unio tuberculatus Bar. is not preoccupied by Obliqiiaria 

 tuberculata Raf., as noted by Vanatta but corrected by 

 Walker ('16). 



The original description of 0. verrucosa and the extremely 

 poor and crude figure indicate an elongated shell, rather closely 

 covered upon the disk by tubercles. This is sufficient to rec- 

 ognize the species : no other shell has tubercles on the disk 

 and is elongated at the same time. Thus, verrucosa stands as 

 the specific name. 



The use of the generic names Quadrula or Tritogonia Ag. 

 ('52) involves a purely taxonomic, not a nomenclatorial, 

 question. 



Genus Cyclonaias Pilsbry n. n. 



Type: Obliqiiaria tuberculata Rafinesque, 1820. 



Cyclonaias tuberculata (Raf.), '20= Quadrula (Rotundaria) tuber- 

 culata, Simpson, '14, p. 80. 



Rotundaria Rafinesque, '20, p. 308 (no type named) ; Herrmannsen, 

 '47, p. 407 (type, Obliquaria subrotunda Raf.) ; Agassiz, '52, p. 48 

 (type, Obliquaria tuberculata Raf.) ; Simpson, '00, p. 794, as subgenus 

 of Quadrula (type, Obliquaria tuberculata Raf.). 



Agassiz and Simpson's conception of Rotundaria with 0. 

 tuberculata as type cannot stand, since Herrmannsen ('47) 



