260 [ FEBRUARY, 
Unio vibex, Cor. New Fresh Water Shells, 31, 4, 3. 
Lea, Synopsis, 30. 
Whiteanus, Lea, 1852, x. 258, 14, 8, Synopsis 33. 
Zeiglerianus, Lea, 1838 (Zieglerianus?) vi. 32,10, 27. Synopsis, 29. 
Chenu, Conchyl. Unio, pl. 24, fig. 2. 
Metrartera, Raf., Aguas. |. . 
Metap. alata. 
U. alata, Say, Nicholson’s Encyclopedia, iv. pl. 4, fig. 2. 
Lam. Anim. sans Vert. 1819, vi. 76. Desh. ed. of Lam. vi. 539. 
Symphynota alata, Lea, iii. 448. U.alatus, Synopsis, 19. 
Barnes, Sillim. Journ. vi. 260. 
Con., Monog., 56, 31. 
Metaptera megaptera, Raf., Ann. v. 34, 80, 20, Poulson’s Trans. 29. 
Symphynota alata, Lea, iii. 448. U. alatus, Synopsis, 19. 
Lymnadia alata, Swains. Malac. 265, 48. 
U. alatus, Kust. Chemn. Unio. 15, 1, 1. 
fragilis.” 
Elliptio fragilis, Raf. Ann. v. 29. Poulson’s Trans. 22. 
U. fragilis, Swatns., Zool. Illust. 1st ser. pl. 171. 
U. fragilis, Say, Amer. Conch. Syn. No. 6. 
Kust. Chemn. Unio, 19, 3, 1. 
U. gracilis, Barnes, Sillim. Journ. vi. 174. 
Symphynota gracilis, Lea, iii. 452. U. gracilis, Synopsis, 19. 
inflata. 
Symphynota inflata, Lea, iv. 99, 14, 28. 
U. inflatus, Coz. Monog. 57, 32. 
Lea, Synopsis, 19. 
' Kust. Chem. Unio, 17, 2, 1. 
U. Alabamensis, Conx., New Fresh Water Shells, p. 67. 
Ohiensis. 
Lastena Ohiensis, Raf. Ann. v.50, Poulson’s Trans. 60. 
U. levissimus, Lea, iii. 444, 13, 23, Synopsis, 19. 
PLEcTOMERUS, Con. 
Shell ‘subalated, obliquely plicated; cardinal teeth very thick, sulcated, the 
posterior lobe directed towards the posterior extremity of the shell; posterior 
muscular impressions scarcely impressed, confluent. 
Plect. atromarginatus. 
U. atromarginatus, Lea, viil. 207, 13, 21, Synopsis, 19. 
Chenu, Conchyl. Unio, pl. 28, fig. 6. 
Boykianus. 
U. Boykianus, Lea, viii. 208, 13, 22, Synopsis, 19. 
Chenu, Conchyl. Unio, pl. 27, fig. 2. 
costatus. 
U. costatus, Raf. Ann. v.49, Poulson’s Trans. 57. 
Con. Monog. 17, 7. 
U. undulatus, Barnes, Sillim. Journ. vi. 120, pl. 2. 
Lea, Synopsis, 20. 
U. latecostatus, Lea, 1845, x. 68, 1,2. 
* I have not quoted Stimpson for this species, because he says that the Ohio 
species is different from the shell usually regarded as the same, which inhabits 
Lake Champlain, and he refers only to the latter. Rafinesque described the 
Western shell. As Say’s U. alatus was found in Lake Erie, I do not know 
whether Agassiz considers it the same as the Ohio river species, or as that of 
Lake Champlain. 
oe 
