90 NEW UNIONIP.E OF THE 



Unio subflavus. pi. 19, fi"-. 70. 



Testa Iscvi, cUiptiea, compressa, postice subbiangulata, inaequilaterali ; valvulis crassis; natibus proniinulis; 

 epidermide vel lutcola vel luteo-castanea, vel obsolete radiata vcl cradiata ; dentibus cardinalibus parvis, 

 subconicis, crenulatis, in utroque valvulvo duplicibu.s ; lateralibus longis, lamellati.s subcurvisque ; luar- 

 garita vel salmonis colore tincta vel albidil et iridescente. 



Shell smooth, elliptical, compressed, subhiangular behind, inequilateral; valves 

 thick ; beaks slightly prominent ; epidermis yellowish, inclined to chestnut ; obsoletely 

 rayed or without rays ; cardinal teeth small, subconical, crenulate, double in both 

 valves ; lateral teeth long, lamellar and somewhat curved ; nacre whitish or salmon 

 color and iridescent. 



Proc. Acad. Nat. Sci. 1857, p. 170. 



Eah. — Walnut Creek, above Macon, Georgia. Bishop Elliott and J. C. Plant. 



My cabinet and cabinets of Bishop Elliott and Mr. Plant. 

 Diam. "9, Length 1-7, Breadth 2-7 inches. 



Shell smooth, elliptical, compressed, inequilateral, subhiangular behind and round 

 before ; substance of the shell thick, slightly thicker before ; beaks slightly prominent ; 

 ligament long and thick ; epidermis yellowish, inclined to chestnut, obscurely rayed 

 or without rays, with rather distant distinct marks of growth ; umbonial slope slightly 

 raised into an obscure angle ; cardinal teeth small, subconical, crenulate, double in 

 both valves; lateral teeth stout, long, lamellar, and somewhat curved; anterior 

 cicatrices distinct, large and well impressed ; posterior cicatrices confluent, rather 

 large and well impressed; dorsal cicatrices deep, rather small and placed above the 

 centre of the cavity of the beaks ; cavity of the shell very shallow and very wide ; 

 cavity of the beaks very small and rounded ; nacre whitish or salmon color and 

 iridescent. 



Soft parts. — Branchial uterus filling nearly the whole of the outer brauchiaj. Bran- 

 chice thin, very large, rounded below, the inner ones much the larger and nearly 

 semicircular, free more than half the length of abdominal sack. Palpi rather large, 

 suboval, united only at the upper part of the posterior edges. Mantle very thin, 

 thickened at the margin. Branchial opening rather small, with small brown papillae 

 on the inner edges. Anal opening rather small, with very minute brownish papillag 

 on the inner edges which are of a deeper brown. Super-anal opening rather small, 

 with a brownish line on the interior margins, united below for a short distance. 

 Color of the mass whitish, inclining to salmon. 



Remarks. — A number of specimens were sent to me by Bishop Elliott. This spe- 

 cies belongs to the extensive compMiatus group. It is more oblique than the type 

 and is near to Stonoisis (nobis.) In all the specimens the nacre was more or less 

 salmon, sometimes very pale, the white predominating. The cardinal teeth are very 

 small. 



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