CHIEFLY OF THE UNITED STATES. 59 



Shell smooth, elliptical, somewhat inflated, inequilateral ; substance of the shell 

 rather thin ; beaks slightly prominent, undulate at the tips and slightly granulose ; 

 ligament short and thin; epidermis straw-yellow, shining and without rays; 

 umbonial slope slightly raised and rounded ; posterior slope narrow elliptical, with 

 two obscure impressed lines in each valve from tlie beaks to the margin ; cardinal 

 teeth small, compressed, crenulate and double in both valves ; lateral teeth rather 

 long, lamellar and straight ; anterior cicatrices distinct, rather small and slightly 

 impressed; posterior cicatrices confluent and slightly impressed; dorsal cicatrices 

 placed on the upper side of the cavity of the beaks ; cavity of the shell rather deep 

 and rounded ; cavity of the beaks shallow and obtusely angular ; nacre whitish, in- 

 clining to salmon, and iridescent. 



Remarks. — This is a small delicate shell, unlike any other I have seen from Asia 

 Minor. A single specimen only was received and this may not be adult. There is 

 but a single mark of gi'owth and that is near the margin. The beaks are perfect 

 and exhibit two rows of granules. In the outline it is very regularly oval, having 

 somewhat the aspect of a young ochraceus, Say, but they differ altogether in the 

 system of undulations of the tips. 



Most of the species from Asia Minor described in this paper were received by Mr. 

 Wheatley through the Rev. E. R. Beadle, of Hartford. 



Unio Natalensis. pi. 20, fig. 57. 



Testa plicata, antice sulcata, oblonga, ad latere planulata, valde intequilaterali, antice rotundata, postice 

 obtuse angulata ; valvulis subcrassis. antice aliquanto crassioribus ; natibus subprominentibu.s, 

 acuminatis, ad apices undulatis ; epidermide luteola, eradiata; dentibus cardinalibus compressis, 

 obliquis corrugatisque ; lateralibus longis, lamellatis subcurvisque ; margarita dilute salmonia-colore 

 tincta et valde iridescente. 



Shell folded, sulcate before, oblong, flattened at the sides, very inequilateral, 

 rounded before and obtusely angular behind ; valves rather thick, somewhat 

 thickened before ; beaks somewhat prominent, acuminate and undulate at the tips ; 

 epidermis yellowish, without rays ; cardinal teeth compressed, oblique and corrugate ; 

 lateral teeth long, lamellar and somewhat curved ; nacre pale salmon color and very 

 iridescent. 



Proc. Acad. Nat. Sci., 1864, p. 113. 



Hah. — Umpingave River, Port Natal, South Africa, Rev, J. McKen. 



Cabinet of the Academy of Natural Sciences. 

 Diam. -54, Length -80, Breadth 1*60 inches. 



Shell folded, sulcate beyond the folds, oblong, flattened at the sides, very inequi- 

 lateral, rounded before and obtusely angular behind ; substance of the shell rather 



