586 ORTMANN— NAYADES OF 



76. Truncilla arc^formis (Lea), 1831. 



Unio arccefoniiis Lea, '31. — Unio arcccforuiis Lewis, '71. — Unio 

 arccrformis Pilsbry & Rhoads, '96. — Trnncilla arccvformis Simp- 

 son, '14, p. 12. 



In the larger and medium rivers : Tennessee, Knox Co., Tenn. ; 

 French Broad at Boyd Creek, Sevier Co. In the Holston locally 

 abundant: Boyd Island, near Knoxville (Pilsbry & Rhoads); Mc- 

 Millan, Knox Co. ; Mascot, Knox Co. ; Gant Island near Straw- 

 berry Plains, Jefferson Co. (Walker coll.) ; McBee Ford, near 

 Hodges, Jefferson Co. ; Turley IMill, Noeton, and Holston Station, 

 Grainger Co. ; Austin Mill, Hawkins Co., Tenn. In the Clinch at 

 Clinch River Station, Claiborne Co. ; and Oakham, Grainger Co., 

 Tenn. 



Type locality: "Tennessee River." Lea (Tr. Amer. Philos. Soc, 

 1834, p. 86) corrects this, saying that, according to Troost, this 

 species is not in the Tennessee, but only in the Cumberland River 

 (meaning, of course, the Tennessee of northern Alabama). 



yy. Truncilla interrupta (Rafinesque), 1820. 



Obliquaria interrupta Rafinesque, '20. — Unio hrevidcns Lea, '31 (not 

 '34, as given by Simpson). — Unio hrevidcns Lewis, '71. — Trun- 

 cilla hrevidcns Simpson, '14, p. 7. 



The identity of Rafinesque's species with that of Lea has been 

 recognized by Conrad, accepted by Kuester and Reeve, and con- 

 firmed by Vanatta ('15, p. 550). But Vanatta does not use the name 

 of interrupta, for reasons which do not hold good,, as shown by 

 Walker ('16, p. 45). The only objection to interrupta is that it is 

 given, originally, from Kentucky and Ohio rivers, while it seems to 

 be absent at least from the Ohio. But we must remember that Lea's 

 hrevidcns also was originally given from Ohio, corrected subse- 

 quently, '34, to Cumberland River. 



In the larger and medium rivers: Tennessee (Lewis), Holston, 

 CHnch, and Powell. In the Powell, up to Rose Hill, Lee Co., Va. ; 

 in the Clinch, up to Clinchport, Scott Co., Va. ; in the Holston up 

 to the North Fork at Hilton, Scott Co., A^a. 



Type locality: "Kentucky and Ohio Rivers." (Probably incor- 

 rect; type from Ohio River, according to Vanatta.) 



