290 NEW UNIONID^E, MELANID^, ETC., 



Hah. — Lake Nicaragua, Central America, Col. E. Jewett. 



Mv cabinet. 

 Diam. 1"9, Length 2-5, Breadth 4-3 inches. 



Shell smooth, suboblong, very much inflated, somewhat inequilateral, rounded 

 behind and obliquely rounded before ; substance of the shell thin ; beaks prominent, 

 large and very much inflated ; ligament rather short, thick and dark brown ; epi- 

 dermis olivaceous, with a single mark of growth, transversely striate, almost sulcate 

 and obscurely radiate ; umbonial slope raised and rounded ; posterior slope wide, 

 elliptical and dark green ; anterior cicatrices distinct, rather large and very slightly 

 impressed ; posterior cicatrices confluent, large and slightly impressed ; dorsal 

 cicatrices placed within the cavity of the beaks; cavity of the shell deep and 

 rather wide ; cavity of the beaks rather deep and rounded ; nacre silver-white, 

 pinkish in the cavity of the beaks and very iridescent 



Remarhs. — A single specimen was sent to me by Col. Jewett, of Utica, N. Y. It 

 was obtained by him as coming from Lake Nicaragua. The remarks as to habitat 

 mentioned in regard to An. Bridgesiana, herein described, may apply to this. In 

 outline and inflation it has a close resemblance to An. doliaris (nobis), from North 

 Carolina, but it is more quadrate, has a diiFerent epidermis and is much more brilliant 

 in the nacre. The ti'ansverse strise are close and well defined, almost forming 

 furrows. On the posterior slope there are a few broad, greenish rays. The 

 nacre is brilliant, but not nearly so much so as in Bridgesiana. The interior, towards 

 the beaks in this specimen, is pinkish. A single mark of growth is prominent 

 towards the margin in this specimen. It cannot be confounded with Bridgesiana, 

 from same habitat, that species being more transverse, of a thinner substance and 

 much more brilliant in the nacre, and the dorsal line is not so straight. It differs 

 from trapezialis, Lam., in not being oblique, and from Forbesiana (nobis) in not being 

 obovate and in not being so solid. I name this fine species after Col. Jewett, who 

 kindly sent it to me. 



Anodonta lenticularis. pi. 41, fig. 102. 



Testa Isevi, subrotunda, compressa, inoequivalva, insequilaterali, antice et postice rotundata ; valvulis 

 Bubtenuibus ; natibus prominulis ; epidermide transverse striata, teuebroso-viridi, redundanter 

 radiata ; margarita cseruleo-alba et valde iridescente. 



Shell smooth, subrotund, compressed, inequivalve, inequilateral, rounded before 

 and behind ; valves rather thin ; beaks a little prominent ; epidermis transversely 

 striate, dark green and very much radiated ; nacre bluish-white and very iridescent. 

 Proc. Acad. Nat. Sci. 1868, p. 95. 



Eab. — Lake Nicaragua, Central America, W. M. Gabb. 



My cabinet. 



