14 NEW UNIONIDiE, MELANID^, ETC., 



nacre prevails. Two specimens only are whitish, and one inclining very slightly to 

 purple. Some specimens are less oblong than others, running almost into elliptical. 



Unio Livingstonensis. pi. 4, fig. 11. 



Testa IsBvi, oblonga, subinflata, fere alata, valde insequilaterali, postice obtuse biangulata, antice rotun- 

 data; valvuHs subtenuibus; natibus subpromineatibus j epidermide teaebroso-fusca, eradiata vel 

 obsolete radiata ; dentibus eardinalibus parvis, lobatis ; lateralibus longis, lam ellatis subrectisque ; 

 margarita cseruleo-alba vel purpurea vel salmonea et valde iridescente. 



Shell smooth, oblong, somewhat inflated, almost winged, very inequilateral, ob- 

 tusely biangular behind and rounded before; valves rather thin; beaks somewhat 

 prominent ; epidermis dark brown, without rays or obscurely rayed ; cardinal teeth 

 small, lobed ; lateral teeth long, lamellar and nearly straight ; nacre bluish white, 

 purple or salmon color and very iridescent. 



Proc. Acad. Nat. Sci., 1863, p. 192. 



Eab. — Livingston's Creek, Brunswick County, North Carolina, E. Emmons, M. D. 



My cabinet and cabinet of Dr. Emmons. 

 Diam. -8, Length 1-4, Breadth 2-2 inches. 



Shell smooth, oblong, somewhat inflated, almost winged, very inequilateral, ob- 

 tusely biangular behind and rounded before ; substance of the shell rather thin ; beaks 

 somewhat prominent ; ligament long, rather thin and dark brown ; epidermis dark 

 brown, on the younger yellowish brown, without rays or obscurely rayed, with 

 rather close marks of growth ; umbonial slope swollen and rounded ; posterior slope 

 rather narrow, imbricate and raised into a high carina ; cardinal teeth small, 

 lobed ; lateral teeth long, lamellar and nearly straight ; anterior cicatrices distinct, 

 rather small, somewhat impressed; posterior cicatrices confluent, large and very 

 slightly impressed; dorsal cicatrices placed immediately over the centre of the 

 cavity of the beaks ; cavity of the shell somewhat deep and wide ; cavity of the 

 beaks very shallow and rounded ; nacre bluish white, purplish or salmon color and 

 very iridescent. 



Remarhs. — Nearly a dozen of this species were sent by Dr. Emmons. None were 

 perfect enough to observe the character of the undulations of the tips. In outline it 

 is very nearly allied to inusitatus, (nobis), but differs in the roughness of the epider- 

 mis, some of the specimens being rough nearly over the whole disk. None of the 

 specimens have the enlargement of the umbones which inusitatus has. At first I 

 thought it might be a variety of hepaticus, (nobis), but that shell is ovately oblong, 

 with a less carina and a smooth, polished epidermis. It is to be regretted that none 

 of the specimens were perfect enough to ascertain the form of the undulations of the 

 beaks. The cardinal teeth are very small, usually double in the left and single in 



