52 University of Michigan 



In the description of both depressa and lincolata Raf. the 

 chief character of this species, great compression and posterior 

 narrow and flat truncation, are mentioned, and thus there is 

 no doubt about the identification. Also the pecuHar color pat- 

 tern is indicated in both. O. ellipsaria Raf. is also identifiable 

 as this species. 



Conrad first pointed out the identity of Rafinesque's species 

 and selected the name lincolata, and thus it has to stand. 



Genus Leptodea Rafinesque, 1820 

 Type: Unio fragilis Raf. 



Leptodea Rafinesque, '20, p. 295 (as subgenus of Unio), no type 

 named; Herrmannsen, '47, p. 584 (type, U. fragilis Raf.), 



Lasmonos Rafinesque, '31, p. 5 (type, fragilis Raf., '31, not fragilis, 

 '20) ; Utterback, '16, p. 151 (type, fragilis Raf., '20; see below). 



Paraptera Ortmann, "ii, p. 368 (type, gracilis Bar., '22,^= fragilis 

 Raf., '20) ; Walker, '18^. p. 72. 



Leptodea, Frierson, '14", p. 6 (type, leptodon Raf., '20). 



Since U. fragilis Raf. has been made the type of Leptodea 

 by Herrmannsen, Paraptera Ort. becomes a synonym having 

 the same type, and the subsequent designation of U. leptodon 

 Raf. as the type by Frierson becomes invalid. 



Utterback in giving as the type of Lasmonos the "Lasmonos 

 fragilis Raf., '20,'' confused Unio (Leptodea) fragilis Raf^ 

 "20, and Lasmonos fragilis Raf., '31. The latter is not identi- 

 fiable (see under Leptodea leptodon). 



Leptodea leptodon (Rafinesque), 1820 



Type locality: Lower Ohio River. 



Unio (Leptodea) leptodon Rafinesque, '20, p. 295, pi. 80, f. 5-7. 

 Anodon purpurascens Swainson, '23. pi. 160. 

 Unio velum Say, '29, p. 293. 



Syrnphynota tcmiissima Lea, '29, p. 453, pi. 11, f. 21. 

 Lasmonos fragilis Rafinesque, '31, p. 5. 



U. leptodon Rai.^^ Symph. tcnuissima Lea ^ ^4;;. purpurascens Sw^ 

 Conrad, '34, p. 70. 



