522 PROCEEDINGS OF THE XATIOSJL M US KIM. 



Subgenus PILEA Simpson, 1900. 

 (Type, Unio personatus Say.) 



Male shell with a wide, shallow, radiating depression in front of 

 the posterior ridge, that of the female with a rounded, foliaceous 

 swelling at the posterior base. Animal with post basal flap of mantle of 

 female very heavy; ovisacs not extending to the top of the marsupium. 



(Group of Truncilla personata.} 



Shell inflated, rather solid, nearly as high as long; female not having 

 a central depression, post basal swelling small. 



t TRUNCILLA PERSONATA Say. 



Unio personatus SAY, New Harm. Diss. IT, No. 20, 1829, p. 300. * FERUSSAO, 

 Guer. Mag., 1835, p. 28.* CONRAD, Monog. Y, 1836, p. 47, pi. xxiv. * HAN- 

 LEY, Test. Moll., 1842, p. 202; *Biv. Shells, 1843, p. 2^2. * CATLOW and 

 REEVE, Conch. Nom., 1845, p. 62. *KUSTER, Conch. Cab. Unio, 1852, p. 48, 

 pi. x, fig. 1.* CONRAD, Pr. Ac. N. Sci. Phila., VI, 1853, p. 254.* II. and A. 

 ADAMS, Geu. Rec. Moll., II, 1857, p. 492. *REEVK, Conch. Icon., XVI, 1864, 

 pi. xv, fig. 64.* P.ETEL, Conch. Sam., Ill, 1890, p. 116. 



* Margarita ( Unio) penonatus LEA, Syn. 1836, p. 33; 1838, p. 23. 

 *Maryaron ( Unio) ptrsonatus LEA, Syn. 1852, p. 35; 1870, p. 38. 

 *Scalenaria ptrsonaia AGASSIZ, Arch, fiir Naturg. 1, 1852, p. 43. 



* Unio pileus LEA, Trans. Am. Phil. Soc., IV, 1834, p. 119, pi. xvm, fig. 47.* CON- 



RAD, New F. W. Shells, 1834, p. 71.* LEA, Obs. 1, 1834, p. 129, pi. xvm, fig. 



47. * FERUSSAC, Guer. Mag., 1835. p. 28. *HANLEY, Test. Moll., 1842, p. 



185; * Biv. Shells, 1843, p. 185. *CATI,OW and REEVE, Conch. Norn., 1845, p. 



62.* CHENU, 111. Conch., 1858, pi. xv, figs. 2, 2a, 2b.* H. and A. ADAMS. Gen, 



Rec. Moll., II, 1857, p. 495. * REEVE, Conch. Icon., XVI, 1864, pi. xv, tig. 64. 



* P.ETEL, Conch. Sam., Ill, 1890, p. 163. 

 * Margarita ( Unio) pileus LEA, Syn. 1836, p. 20; 1838, p. 17. 

 *Murgaron ( Unio) pileus LEA, Syn. 1852, p. 24. 



* Unio capillaris LEA, Tran. Am. Phil. Soc., V, 1834, p. 29, pi. n, fig. 2 ; * Obs. 1, 18:34, 



p. 141, pi. n, fig. 2.* FERUSSAC, Guer. Mag., 1835, p. 29. 



Ohio Kiver drainage. Rare. 



(Group of TruHcilla pcrplexa.} 



Shell of the male with median and posterior radiating ridges, both of 

 which are usually somewhat nodose; postbasal expansion of the female 

 rounded, large, thin, placed far back. 



t TRUNCILLA PERPLEXA Lea.' 



* Unio perplcxua LEA, Trans. Am. Phil. Soc., IV, 1831, p. 112, pi. xvn, fig. 42; * Obs. 



I, 1834, p. 122, pi. xvii, fig. 42.* HANLEY, Test. Moll., 1842, p. 181 ; * Biv. 

 Shells, 1843, p. 181, pi. xxn, fig. 39. " CATLOW and REKVE, Conch. Norn., 1845, 

 p. 62. "H. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 496. *CHKXU, 111. 

 Conch., 1858, pi. xvm, figs. 5, 5o, 56. 

 'Margarita ( Unio) plexus LEA, Syn. 1836, p. 17; 1838, p. 16. 



'Lea's species was published, according to Scudder (Bibliography of Isaac Lea, 

 p. 3), in the latter part of 1831. Rafinesque published a species, "Truncilla, Unio 

 perplexus,'' in the Continuation of a Monograph in October, 1831, which I can not 

 identify. I do not know which uauie appeared first, but I think it best to retain 

 the well-known and properly described name of Dr. Lea. 



