20 DESCRIPTION OF NEW 
ligament not very long and moderately thick; epidermis chestnut-brown, with very 
distant marks of growth; posterior slope wide, rather flattened, with two raised lines 
passing from the beaks to the posterior margin; umbonial slope large and rounded; 
cardinal teeth large, crenulate, double in the left and single in the right valve; lateral 
teeth very long, somewhat curved and thickened towards the posterior end, separated 
from the cardinal tooth; anterior cicatrices large and distinct; posterior cicatrices large 
and distinct; dorsal cicatrices small, and placed nearly in the centre of the beaks; palleal 
cicatrix deeply impressed; cavity of the shell wide, not very deep; cavity of the beaks 
exceedingly small and rounded; nacre silvery white. 
Remarks.—A single specimen only of this fine shell has come under my notice, and it 
belongs to the cabinet of my friend Major Le Conte. Itis a member of that great group of 
which UY. complanatus is the type, but it differs from that species somewhat in outline, in 
being inflated over the umbonial slope, and in having a smoother epidermis. 
I dedicate this fine species to the memory of the great zoologist, Baron Cuvier. 
Unio Forpesianus. Pl. XVI. Fig. 17. 
Testa levi, triangulari, subcompressd, inequilaterali, posticé angulatd; valvulis subcrassis; natibus sub- 
prominentibus, ad apices undulata; epidermide castaneo-fusca; dentibus cardinalibus acuminatis, subgrandibus; 
(ateralibus longis subrectisque; margarita vel alba vel purpurea et iridescente. 
Shell smooth, triangular, rather compressed, inequilateral, angular behind, valves rather thick; beaks rather 
prominent, undulated at the tip; epidermis chestnut-brown; cardinal teeth rather large and pointed; lateral teeth 
large and nearly straight; nacre white or purple and iridescent. 
Hab. Savannah River. Major Le Conte. 
My cabinet and cabinet of Major Le Conte. 
Diam. .8, Length 1.2, Breadth 1.8 inches. 
Shell smooth, triangular, rather compressed, inequilateral, acutely angular behind, 
slightly flattened before the umbonial slope; substance of the shell rather thick, thinner 
behind; beaks rather prominent and rather coarsely undulated at the tip; ligament rather 
short and moderately thick; epidermis chestnut-brown, lines of growth distant and dis- 
tinct, sometimes rayed; umbonial slope raised into rather an acute angle; posterior slope 
flattened and furnished with numerous angular crumpled folds; cardinal teeth rather large, 
pointed and crenulate; lateral teeth long and nearly straight; anterior cicatrices distinct; 
posterior cicatrices distinct; dorsal cicatrices placed on the under side of the cardinal 
teeth; cavity of the shell rather small and rounded; cavity of the beaks shallow and 
angular; nacre white or purple and iridescent, 
Remarks.—Several of these of different ages, were given to me by my friend Major 
Le Conte, to whom I owe the possession of so many new species. It is allied to U. incras- 
satus, (Nobis,) but is not so transverse. In the young, the epidermis is rather polished, 
and some of them have greenish rays over the middle of the disk. The smallest of them 
all is purple in the nacre and beautifully iridescent. Some of the specimens scem to be 
devoid of rays altogether. 
Named in honour of Professor E. Forbes, of King’s College, London. 
