﻿TRUNCILLA c 



Length (male) 55, heig-ht 43, diam. 31 mm. 



Length (female) 48. height 30, diam. 22 mm. 



Lower Alabama and Tombigbee River drainage. 



Type locality, Alabama River at Claiborne. 

 JJnio penitus Conrad, New F. W. Shells, 1834, pp. 33, 70, pi 



V, fig. I. — Chunu, Bib. Conch., ist sen, IH, 1845, P- 18, pi 



III, fig. 9. — Reeve, Conch. Icon., XVI, 1864, pl- xiv, fig. 55 

 Margarita (Unio) penitus Lea, Syn., 1836, p. 19; 1838, p. 16 

 Margaron (Unio) penitus Lea. Syn., 1852, p. 24; 1870, p. 36, 

 Trnncilla penita Simpson, Syn., 1900, p. 518. 



Truncieea compacta (Lea). 



Shell subtriangular, somewhat inflated, solid, inequilateral ; 

 beaks full and high ; surface with inconspicuous growth lines, 

 the posterior end being lightly radially striate ; epidermis 

 slightly yellowish-green with a few faint, broken, darker rays ; 

 pseudocardinals ragged, double in the left valve, often treble 

 in the right ; laterals short, double in the left valve, scarcely 

 double in the right ; muscle scars impressed ; nacre white. 

 Male shell subtriangular, generally having the greatest diam- 

 eter at the well-developed, narrowly rounded posterior ridge. 

 Female shell subrhomboid o'r subtriangular, the marsupial 

 swelling but slightly raised, not very strongly radially ridged 

 or toothed, thin and somewhat excavated within, with large 

 deep, posterior scars. 



Length (male) 44, height 36, diam. 22 mm. 



Length (female) 27^ height 25, diam. 20 mm. 



Alabama and Tombigbee drainage. 



Type locality, Etowah and Connasauga Rivers, Ga. 

 Unio cotnpactns Lea, Proc. Ac. Nat. Sci. Phila., Ill, 1859, p. 



154; Jl. Ac. Nat. Sci. Phila.. IV, 1859, p. 218, pl. xxviii, fig. 



98 ; Obs. VII, 1859, p. 36, pl. xxviiT, fig. 98. 

 Margaron (Unio) compactus Lea, Syn., 1870, p. 36. 

 Truncilla penita, (part), Simpson, Syn., 1900, p. 518. 



The female shells of this species, so far as I have observed, 

 are generally, though not always, shorter than those of T. 



