NO. 1205. SYNOPSIS OF THE NAIADES— SIMPSON. 749 



t PLEUROBEMA ACUENS Lea. 



* Unio aouens Lea, Pr. Ac. Nat. Sci. Phila., 1, 1871, p. 190; ** Jl. Ac. Nat. Sci. Phila., 



VIII, 1874, p. 27, pi. VIII, fig. 24; *Obs., XIII, 1874, p. 31, pi. viii, fig. 24.— 

 *B. H. Wright, Check List, 1888.— * P^tel, Conch. Sam., Ill, 1890, p. 143. 



Tennessee River system. 



t PLEUROBEMA ORNATA Lea. 



* irnio ornatus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 4; * Jl. Ac. N. Sci. Phila., 



V, 1862, p. 85, pi. xi, fig. 234; ^ Obs., VIII, 1862, p. 89, pi. xi, fig. 234.— 

 *P^tel, Conch. Sam., Ill, 1890, p. 162. 



* Margaron {Unio) ornatus Lea, Syn., 1870, p. 57.i 



Alabama. 



t PLEUROBEMA APPRESSA Lea. 



* Unio appressus Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 189 ; * Jl. Ac. N. Sci. Phila., 



VIII, 1874, p. 12, pi. Ill, fig. 8.— *Obs., Ill, 1874, pi. in, fig. 8.— *B. H. 



AVright, Check List, 1888. 

 *Unio argenieiis Sowerby, Conch. Icon., XVI, 1866, pi. xxxvii, fig. 204. 

 \Unio tusciimhiensis Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 191; * Jl. Ac. N. Sci. 



Phila., VIII, 1874, p. 11, pi. in, fig. 7; *0b8.,XIII, 1874, p. 15, pi. iii, fig. 7.— 



*B. H. Wright, Check List, 1888. 



* Unio flavidus Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 156; * Jl. Ac. N. Sci. Phila., 



Vlil, 1874, p. 28, pi. IX, fig. 25; *Obs., XIII, 1874, p. 32, pi. ix, fig. 25.— 

 *B. H. W^RiGHT, Check List, 1888. 



Tennessee Eiver system. 



t PLEUROBEMA TESSERUL.^ Lea. 



* Unio tesserulce Lea, Pr. Ac. N. Sci. Phila., VI, 1861, p. 392; * Jl. Ac. N. Sci. Phila., 



VI, 1866, p. 40, pi. XV, fig. 39; * Obs., XI, 1867, p. 44, pi. xiv, fig. 38.—* B. H. 

 Wright, Check List, 1888. 



*Margaron ( Unio) tesserulce Lea, Syn., 1870, p. 36. 



Nolacliucky River, Tennessee. 



t PLEUROBEMA VALIDA Lea. 



*Unio validus Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 189; * Jl. Ac. N. Sci. Phila., 

 VIII, 1874, p. 6, pi. I, fig. 2; *Obs., . Ill, 1874, p. 10, pi. i, fig. 2.— * B. H. 

 Wright, Check List, 1888. 



Tennessee. 



t PLEUROBEMA ABACUS Haldeman.^ 



* Unio abacus Haldeman, Jl. Ac. N. Sci. Phila., VIII, 1842, p. 202. — 'Conrad, 



Pr. Ac. N. Sci. Phila., VL, 1853, p. 244.— *H. and A. Adams, Gen. Rec. Moll., 



II, 1857, p.495.— "B. H. Wright, Check List, 1888.— * P.etel, Conch. Sam., 



III, 1890, p. 143. 



* Marf/aron {Unio) afcacws Lea, Syn., 1852, p. 24; 1870, p. 38 



Tennessee and southwest Virginia. 



' The only specimen I have seen (the type) is a young shell, which I can not refer 

 with certainty to any other species. 



^As this species was not figured and I have not seen the type, I am unable to be 

 absolutely certain what it is. In the Lea collection are four specimens labeled 

 " Unio abacus Hald.," which are close to appressus. 



