540 ORTMANN—NAYADES OF 
Obliquaria flexuosa bullata Raf., ’20 (Internat. Rules of Zool. 
Nomencl., Art. 11), and since the identity of O. retusa is not quite 
certain, the name given by Lea becomes available. 
I cannot see anything but an individual variation in what Lea has 
called U. pernodosus. This is given from “ North Carolina,” accord- 
ing to Lea probably from the tributaries of the Tennessee (in the 
mountains). But its occurrence in these parts has never been con- 
firmed. U. sphericus (?), reported by Pilsbry & Rhoads from near 
Chattanooga, surely is this. 
This species prefers the larger rivers, and is not rare in them, 
chiefly so in the Tennessee at and below Knoxville. I traced it up 
the Clinch to Offutt, Anderson Co., Tenn., but a single specimen is 
in the Walker collection also from the Powell, at Bryant Shoals, 
Claiborne Co., Tenn. In the Holston, it goes up to McBee Ford, 
near Hodges, Jefferson Co., and in the French Broad, it reaches the 
lower part of the Nolichucky at Chunn’s Shoals, Hamblen Co., Tenn. 
Type locality: Ohio. 
14. QUADRULA VERRUCOSA (Rafinesque), 1820. 
Obliquaria verrucosa Rafinesque, ’20.—Unio conjugans Wright, 
Naut., 13, 99, p. 89 —Quadrula tuberculata Ortmann, ’12b, p. 
254 (anatomy ).—Tritogonia tuberculata and T. conjugans Simp- 
son, 14, pp. 318, 322—Tritogonia verrucosa Vanatta, ’15, p. 554. 
—Quadrula verrucosa Utterback, ’16, p. 62. 
This form has been previously reported, as U. conjugans, only 
from Hiwassee River, and the type (examined in Washington) is 
indeed a remarkable shell, an apparently stunted, shortened male of 
this species (individual abnormity).’ That this species is actually 
present in the lower part of the Hiwassee, in Meigs Co., Tenn., is 
shown by three fine specimens in the Walker collection (Adams). 
It is very remarkable that I did not find a trace of this striking 
species in any other part of the upper Tennessee drainage. 
Type locality: Ohio River. 
Note: Below the Walden Gorge, in Sequatchie River, Tenn., and 
the Tennessee drainage in northern Alabama, this species is more 
abundant, both in the Tennessee River and its tributaries (Paint 
