18 University of Michigan 
QUADRULA VERRUCOSA (Rafinesque), 1820 
Type locality: Ohio River. 
Obliquaria verrucosa Rafinesque, ’20, p. 304, pl. 81, f. 10-12. 
Unio tuberculatus Barnes, ’23, p. 125, pl. 7, f. 8. 
U. verrucosus Raf. =U. tuberculatus Bar., Conrad, ’34, p. 72; Ferus- 
SEY) Ry th 2 
Tritogonia tuberculata (Bar.), Simpson, ’00°, p. 608; ’14, p. 318. 
Trit. verrucosa (Raf.) =Trit. tuberculata (Bar.), Vanatta, ’15, p. 
554 (‘“‘types” examined). 
Obl. verrucosa (Rat.) = Trit. tuberculata (Bar.), Walker, ’16°, p. 45, 
and ‘18, p. 170 (“if identifiable’). 
Quad, verrucosa (Raf.), Utterback, ’16, p. 62; Ortmann, ’18, p. 540. 
Unio tuberculatus Bar. is not preoccupied by Obliquaria 
tuberculata Raf., as noted by Vanatta but corrected by 
Walker (716). 
The original description of O. 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. 
(752) involves a purely taxonomic, not a nomenclatorial, 
question. 
Genus CycrionatAs Pilsbry n. n. 
Type: Obliquaria 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, 752, p. 48 
(type, Obliquaria tuberculata Raf.) ; Simpson, ’00, p. 794, as subgenus 
of Quadrula (type, Obliquaria tuberculata ait) e 
Ygassiz and Simpson’s conception of Rotundaria with O. 
tuberculata as type cannot stand, since Herrmannsen (’47) 
