UNITED STATES. 29 



brown striato, -with indistinct linos of growth ; umbonial slope raised and obtusely 

 angular; posterior slope rather broad, with two raised lines on each valve from the 

 beak to posterior margin; cardinal teeth somewhat large, crenulate, deeply striate 

 and double in both valves; lateral teeth rather long, thick, granulate, thickened 

 towards the end and somewhat curved ; anterior cicatrices distinct and very deeply 

 impressed ; posterior cicatrices large, confluent and well impressed ; dorsal cicatrices 

 placed above the centre of the cavity of the beaks ; cavity of the shell rather deep and 

 wide ; cavity of the beaks very shallow and rounded ; nacre purple and iridescent. 



Soft parts. — Bmncldal uterus not charged, but several had ova in ovaria. Brandiuv 

 large and regularly rounded below, the inner one very much the larger, free about 

 half the length of the abdominal sack. PaJpi small, thin, subtriangular, united 

 nearly half way down the posterior edges. Mantle thin, slightly colored. Brancliial 

 opening with small dark brown papilltc. Anal opening with very small dark brown 

 papillte. Svper-anal opening long, slightly colored on the inner edges, united at the 

 lower part. Color of the mass whitish. 



Remarks. — Quite a large number of specimens wore kindly sent to me by Mr. 

 Downie, in alcohol, but none had ova in the branchial oviducts. The embryonic form 

 could not, therefore, be observed, nor could the form of the branchial uterus. This 

 species is nearly allied to Lecontiamis (nobis), and forms one of a group of which the 

 latter may be considered the type. The JDoivniei is more oval and not so smooth and 

 shining on the side. The female is enlarged on the umbonial slope and the young are 

 much rayed, Avhile the old have no appearance of them. These rays are groen. Two 

 of the specimens had very distinct ventral cicatrices. 



I dedicate this species to T. C. Downie, Esq., of Brunswick, Georgia, to whom I am 

 indebted for many fine Georgian^Unionidcc. 



Unio Hazlehurstiaxus. PL 2G, fig. 92. 



Tcstu IjBvi, ti-an.sversS, subc3'lindracea, posticd biangulata, vald6 inxquilaterali ; valvulis subtenuibus ; 

 natibus proiuinulis ; epidcrmido nigricante, subtilite striata ; dentibus cardinalibus parvis, compresse- 

 fonicis ; lateralibus proelongiii!, lamcllatis subrectisque ; margarita purpurascentc et valde iridcsccntc. 



Shell smooth, transver.^e, subcylindrical, biangular behind, very inequilateral ; 

 valves rather thin ; beaks a little prominent ; epidermis blackish, minutely striate ; 

 cardinal teeth small, compressed and conical ; lateral teeth very long, lamellar and 

 nearly straight ; nacre purplish and very iridescent. 

 Proc. Acad. Nat. Sci., 1858, p. 166. 



Hub. — Satilla River, Camden County, Georgia. T. C. Downie, Esq. 



My cabinet and cabinet of Mr. Downie. 

 D'l^ui. -9, Length 1-4, Breadth 3 inches. 



Shell smooth, transverse, subcylindrical, biangular behind, disposed to be abruptly 

 rounded before, very inequilateral ; substance of the shell rather thin ; beaks slightly 



