522 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxii. 



Sabgenus PILEA Simpson, 1900. 



(Type, Unio 2)ei'sonatus Saj .) 



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 per sonata.) 



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. 309.—* Ferussac, 

 Guer. Mag., 183.5, p. 28.—* Conrad, Monog. V, 1836, p. 47, pi. xxiv.- * Han- 

 ley, Test. Moll., 1842, p. 202; * Biv. Shells, 1843, p. 2C2.— ^Catlow and 

 Eeeve, 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.—* H. and A. 

 ADAMS^Geu. Eec. Moll., II, 1857, p. 492.— * Reeve, Conch. Icon., XVI, 1864, 

 pi. XV, fig. 64.—* P^TEL, Conch. Sam., Ill, 1890, p. 116. 



* Margarita ( Unio) personaiiis Lea, Syn. 1836, p. 33; 1838, p. 23. 

 ^Marcjaron ( Unio) personatxis Lea, Syn. 1852, p. 35 ; 1870, p. 38. 

 * Scalenaria ptrsonaia Agassiz, Arch, fiir Natnrg. I, 1852, p. 43. 



* Unio pileus Lea, Trans. Am. Phil. Soc. , IV, 1834, p. 119, pi. xviii, fig. 47.—* CON- 



KAD, New F.W. Shells, 1834, p. 71.— * Lea, Obs. 1,1834, p. 129, pi. xvm, fig. 



47.— * Ferussac, Guer. M;ig., 1835, p. 28.— * Hanley, Test. Moll., 1842, p. 



185; * Biv. Shells, 1843, p. 185.— *Cateow and Reeve, Conch. Nom., 1845, p. 



62.—* Chenu, 111. Conch., 1858, pi. xv, figs. 2, 2a, 2&.— * H. and A. Adams, Gen. 



Eec. Moll., II, 1857, p. 495.— * Reeve, Conch. Icon., XVI, 1864, pi. xv, fig. 64.— 



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

 ""Margarita ( Unio) pileiis Lea, Syn. 1836, p. 20; 1838, p. 17. 

 *Margaron ( Unio) pileus Lea, Syn. 1852, p, 24. 



* Unio capillaris Lea, Tran. Am. Phil. Soc, V, 1834, p. 29, pi . ii, fig. 2 ; * Obs. 1, 1834, 



p. 141, pi. II, fig. 2.—* Ferussac, Guer. Mag., 1835, p. 29. 



Ohio Kiver drainage. Eare. 



(Group of Triowilla perpiexa.) 



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 perplexus Lea, Trans. Am. Phil. Soc, IV, 1831, p. 112, pL x vii, fig. 42 ; * Obs. 



I, 1834, p. 122, pi. XVII, fig. 42.— * Hanley, Test. Moll., 1842, p. 181; * Biv. 

 Shells, 1843, p. 181, pi. xxii, fig. 39.—* Catlow and Reeve, Couch. Nom., 1845, 

 p. 62.— •■ H. and A. Adams, Gen. Eec. Moll., II, 1857, p. 496.—* Chenu, 111. 

 Couch., 1858, pi. XVIII, figs. 5, 5a, 5h. 

 "" Margarita ( Unio) perplexus 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. Eafiuesque 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 name appeared first, but I think it best to retain 

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



