FRESH WATER AND LAND SHELLS. 43 
Wablamat river, in Oregon. It differs in being a smaller species, in being more inflated, 
and particularly so in the superior part. In this shell the umbonial slope is smaller from 
the beaks to the posterior dorsal margin. In the Nuétadliana the upper portion of the 
umbonial slope is flattened, but it enlarges towards the posterior basal margin, and there 
makes the greater diameter. In the Californiensis the greatest diameter is about the 
middle of the disk, and there is a marked difference in the wing, which is by no means so 
much elevated. 
Anovonta Trautwintana. Pl. XXVI. Fig. 48. 
Testa levi. oblonga, subinflata, inequilaterali, e natibus lineatis; valvulis crassis ; natibus prominulis, ad 
apices minuté undulata ; epidermide virido-olivaced, rugoso-striatd; margarita argented et iridescente. 
Shell smooth, oblong, somewhat inflated, inequilateral, with a line from the beaks; valves thick; beaks some- 
what prominent, at the tips minutely undulated; epidermis greenish-olive and roughly striate; nacre silvery and 
iridescent. 
Hab. Carthagena, South America, John C. Trautwine, Esq. : 
My cabinet and cabinet of the Academy of Natural Science. 
Diam. .9, Length 1.5, Breadth 2.5 inches. 
Shell smooth, oblong, somewhat inflated, inequilateral, obtusely rounded before, subalate 
behind, with a line from the beaks to the posterior margin; substance of the shell thick; 
beaks somewhat prominent, submedial, at the beaks very minutely undulated; ligament 
very long and thin, not protruding above the dorsal line of the valvesyepidermis greenish- 
olive, and roughly striate, quite imbricate behind, without rays; umbonial slope elevated 
into a carina; anterior cicatrices distinct; posterior cicatrices confluent; dorsal cicatrices 
none; palleal cicatrix slightly impressed; cavity of the shell rather deep and rounded; 
cavity of the beak very shallow and subangular; nacre silvery white, with minute strie 
from the beaks towards the margin; iridescent. 
Remarks.—The friends of Mr. Trautwine owe to him the possession of this interesting 
species, of which he brought many specimens, and liberally distributed them. It differs 
from any South American species which has come under my notice. It is a much 
smaller species than An. trapezialis, Lam., rougher in the epidermis and more oblong. 
Some of the specimens are somewhat greenish, others yellowish-olive. The triangular 
fosset at the end of the ligament, so usual in the South American Natades, is very per- 
ceptible in this species. 
In outline, it is allied to ¢etragona, (Nobis.) 
Anoponta Wueatteyi. Pl, XXVI. Fig. 49. 
Testa levi, transversd, subinflatd, gibbosd, valdé inequilaterali, postice angulatd, antice irregulariter 
rotundata; valvulis crassis; natibus tumidis, parum elevatis, feré terminalibus; epidermide cinnamomed, 
eradiata; margarita salmonis colore tincta et valde iridescente. 
Shell smooth, transverse, rather inflated, gibbous, very inequilateral, angular behind, irregularly rounded 
before; valves thick ; beaks swollen, a little elevated and almost terminal; epidermis cinnamon-red and rayless; 
nacre salmon-coloured and very iridescent. 
