•,*() DESCRIPTION OF NEW 



ligament not very long antl 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 tectii 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. It is a member of that great group of 

 which V. 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 Forbesianus. pi. XVL Fig. 17. 



Tentn livvi, triangulari, subcompressd, inequilaterali, postice angulata; valvulis suhcruHHis ; nulihus mib- 

 jiroininentibua, ad apices itndiduln; epidcrmidc caalaneo-fuscd; dciitibiis cardlnulibus acuminatis, subgrundibus; 

 laleralibus longis subreclisque; margarila vel ulbii vel purpurea ct iridcsccnlc. 



Shell smoolh, 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 while 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 rathei 

 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, 

 ])ointed 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 1 owe the possession of so many new species. It is allied to U. incras- 

 salus, (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 seem to be 

 devoid of rays altogether. 



Named in honour of Professor E. J'orbes, of King's College, London. 



