46 NEW CNIONID^ OF THE 



closer. It is not easy to confound it with Baveneliana (nobis), from South Carolina, 

 that shell being more transverse and more cylindrical, while at the same time it has 

 like Elowahensis, but a single tooth in each valve. 



Margaritana triangulata. pi. 32, fig. 111. 



Testa laevi, triangular!, valde inflata, postice angulata, subDequilaterali ; valvulis subtenuibus, antice crassior- 

 ibus; natibus prominentibus, tumidis, ad apices rugoso-undulatis ; epidermide tenebroso-castanea, 

 valde radiata ; dentibus cardinalibus parvis, erectis, crenulatis, in utroque valvulo unicis ; margarita 

 vel alba vel salinonis colore tincta et iridescente. 



Shell smooth, triangular, very much inflated, angular behind, nearly equilateral ; 

 valves rather thin, thicker before ; beaks prominent, swollen, rugosely undulate at 

 the tips ; epidermis dark brown, very much radiate ; cardinal teeth small, erect, 

 crenulate and single in both valves ; nacre white or salmon color and iridescent. 

 Proc. Acad. Nat Sci. 1858, p. 138. 



Eah. — Upper Chattahoochee, Georgia, Bishop Elliott. Columbus, Georgia, Dr. 

 Boykin and J. Postell. Polato County, Georgia, Rev. G. White. Sawney's Creek, 

 South Carolina, Dr. Blanding. 



My cabinet and cabinets of Bishop Elliott, J. Postell and Dr. Lewis. 

 Diam. 1-2, Length 1-5, Breadth 2-2 inches. 



Shell smooth, triangular, very much inflated, angular behind and regularly rounded 

 before, nearly equilateral ; substance of the shell rather thin, thicker before ; beaks 

 prominent, much swollen and rugosely undulate at the tips ; ligament very short, 

 rather thick and light brown ; epidermis dark brown, in the young yellowish, very 

 much radiated, smooth and shining ; umbonial slope very much raised and almost 

 acutely angular ; posterior slope wide, cordate, usually covered with very small folds 

 and wrinkles, with one raised line on each valve from the beak to the posterior margin ; 

 cardinal teeth small, compressed, erect, slightly curved, crenulate and single in both 

 valves; anterior cicatrices confluent, large and rather deeply impressed; posterior 

 cicatrices confluent, large and very slightly impressed ; dorsal cicatrices placed under 

 the plate and round the base of the cardinal tooth ; palleal cicatrix rather broad and 

 distant from the margin ; cavity of the shell very deep and rounded ; cavity of the 

 beaks deep and angular ; nacre Avhite or salmon color and iridescent. 



Soft iMvts. — Branchial uterus occupies the whole length of the outer branchife, 

 presenting an oblong shape, and quite massive with the included embryos, being over 

 an eighth of an inch thick and striate. Branchio} large, nearly semicircular, inner 

 one the larger, united to the abdominal sack the whole length. Palpi very long and 

 subfalcate, united above more than half way down the posterior edges. Mantle thin, 

 thickened towards the posterior portion, where it is angular below the branchial 

 opening, maculate with square brown spots on the outer posterior margin. Branchial 

 opening rather large, with numerous small brownish papillce. Aiml opening rather 



