540 ORTMANN— NAYADES OF 



Obliquaria flexuosa bulla fa Raf., '20 (Internat. Rules of Zool. 

 Nomencl., Art. ii), and since the identity of 0. 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. sphcericiis ( ?), 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 CHnch 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. OuADRULA VERRUCOSA (Rafinesque) , 1820. 



Obliquaria z'errucosa Rafinesque, '20. — Unio conjugans Wright, 

 Naut., 13, '99, p. 89. — Quadrula tubercidata Ortmann, '126, p. 

 254 (anatomy). — Tritogonia tubercidata and T. conjugans Simp- 

 son, '14, pp. 318, 322. — Tritogonia verrucosa Vanatta, '15, p. 554. 

 — Qnadrida 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 



