gy NEW UNIONID.li OF THE 



Unio fumatus. pi. 18, fig. G8. 



Test;! Isevi, ellipticii, compressa, posticfe biangulata, valde inaequilaterali ; v.ilvulis subtenuibus; natibus 

 subprominentibus ; epidermide tenebroso-fuliginosa et eradiata; dentibus cardinalibus paiviusculis 

 crenulatisque ; lateralibus sublongis, subcrassis subrectisque ; margarita purpurescente et valde irides- 

 cente. 



Shell smooth, elliptical, compressed, biangular behind, very inequilateral ; valves 

 rather thick ; beak somewhat prominent ; epidermis dark smoke color, without rays ; 

 cardinal teeth rather small and crenulate ; lateral teeth rather long, somewhat thick 

 and nearly straight ; nacre purplish and iridescent. 

 Proc. Acad. Nat. Sci., 1857, p. 171. 



Hab. — Chattahoochee River, near Columbus, Georgia, Bishop Elliott ; and Hospa- 

 liga Creek, Alabama, Georgia, Dr. Neisler. 



My cabinet and cabinets of Bishop Elliott and Dr. Lewis. 

 Diam. -7, Length 1-3, Breadth 2-4 inches. 



Shell smooth, elliptical, compressed, very inequilateral, biangular behind and 

 round before ; substance of the shell rather thick ; beaks somewhat prominent ; liga- 

 ment rather short and somewhat thick ; epidermis dark smoke color, inclining to deep 

 brown, shining on the umbones and striate near the margin, without rays, with rather 

 distant lines of growth ; umbonial slope slightly raised into an obscure angle ; car- 

 dinal teeth rather small, crenulate, single in the right and double in the left valve ; 

 lateral teeth rather long, somewhat thick and nearly straight; anterior cicatrices dis- 

 tinct, rather large and well impressed ; posterior cicatrices confluent and well im- 

 pressed ; dorsal cicatrices placed on the under side of the plate posterior to the car- 

 dinal teeth ; cavity of the shell shallow and wide ; cavity of the beaks very shallow 

 and slightly rounded ; nacre purplish and iridescent. 



Soft Parts. — Branchial uterus not charged, but ova were found in the ova- 

 rium. Branchice very large, much rounded below, the inner ones much the 

 larger, free about two-thirds length of abdominal sack. Pal^n large, oblique, subtri- 

 angular, united about one-third down the posterior edges. Mantle very thin, thickened 

 at the margin, and slightly colored on the edges. BrancJdal opining large, indented, 

 with numerous small brownish papillae. Anal opening large, with a crenulated 

 brownish inner edge. Super-anal opening very large, not united below, but free with 

 the anal opening.* Color of the mass whitish. 



Remarks. — Several specimens were received from the two above named localities. 

 This species belongs to the cmnplanatus group and is most nearly allied to wquaius 

 (nobis). It is rather less inequilateral, and is not so high on the posterior slope. It 

 is also darker in the epidermis, and is not rayed like that species. Its double angle 

 behind is not so wide. 



*This is very unusual, and possibly the want of .attacbmcnt may be accidental, but there is no appearance 

 of the edges being ruptured or forced apart. 



