36 DESCRIPTION OF NEW 
Hab. Alabama, Mr. C. M. Wheatley. 
Cabinet of Mr. Wheatley. 
Diam. .5, Length .8, , Breadth 1.3 inches. 
Shell smooth, elliptical, rather inflated, inequilateral, angular behind; substance of the 
shell a little thick; beaks somewhat prominent, rounded, ligament short and thin; epider- 
mis chestnut-coloured, shining, obsoletely rayed, with rather distant marks of growth; 
posterior slope rather depressed; umbonial slope slightly raised and round, cardinal teeth 
rather small, compressed, very oblique, crenulate and double in both valves; lateral teeth 
rather long, lamellar, curved and separated from the cardinal teeth; anterior cicatrices 
distinct; posterior cicatrices confluent; dorsal cicatrices placed on the under side of the 
plate; cavity of the shell rather deep and regularly oval; cavity of the beaks small and 
subangular; nacre salmon coloured. 
Remarks.—This is a small, regular and pretty-looking shell, of which only one specimen 
was in Mr. Wheatley’s collection. I could not place it in any species known to me. It 
may not be a fully grown specimen. It is nearest in outline to U. constrictus, Con., in 
those specimens where the margin is not constricted, which is often the case. It differs 
from it in being a thicker shell, more regularly oval, and being fuller on the umbones and 
on the umbonial slope. In the rays it also differs, having fewer, and these being more 
distant. It is also rounder on the posterior margin. The nacre of the specimen before . 
me is of a pale salmon colour, inclining to rose. Other specimens will be likely to vary 
in colour. 
Unio Troscneianus. Pl. XXIII. Fig. 39. 
Testa levi, subobliqua, convexiuscula, ineequilaterali, postice subangulata; valvulis crassis; natibus sub- 
grandibus; epidermide bruneo-oliva, striata, eradiata; dentibus cardinalibus parvis, granulatis; lateralibus 
brevis, crassis reclisque; margarita alba et iridescente. 
Shell smooth, suboblique, somewhat convex, inequilateral, subangular behind; valves thick; beaks rather large; 
epidermis brownish-olive, striate, without rays; cardinal teeth small, granulate; lateral teeth short, thick and 
straight; nacre white and iridescent. 
Hab. Coosawattee river, Murray county, Georgia, Dr. Boykin. 
My cabinet. 
Diam. .7, Length 1.1, Breadth 1.5 inches. 
Shell smooth, rather oblique, somewhat convex, inequilateral, subangular behind, 
rounded before; substance of the shell thick, thinner behind; beaks rather large, sub- 
medial; ligament rather short and thin; epidermis brownish-olive, striate, without rays, 
and with very close marks of growth; posterior slope somewhat compressed; umbonial 
slope rounded; cardinal teeth small, granulate, single in the right and double in the left 
valve; lateral teeth short, thick and straight; anterior cicatrices distinct, posterior cica- 
trices distinct; dorsal cicatrices placed on the under side of the plate; palleal cicatrix well 
impressed ; cavity of the shell rather shallow and rounded; cavity of the beaks very shal- 
low and obtusely angular; nacre white and iridescent. 
Remarks.—Several specimens are before me, neither of which have perfect beaks. 
