398 NEW EXOTIC UNIONID^J. 



Unio occatus. PI. 50, fig. 304. 



Testa plicata, elliptica, rugoso-occata, coinpressa, valde insequilaterali, postice biangulata, antice regu- 

 lariter rotundata; valvulis crassiusculis ; natibus prominulis, valde cornpressis, ad apices plicis pul- 

 chris divaricatis ; epidermide luteo-oliva et valde rugosa ; dentibus cardinalibus parvis, cornpressis, 

 obliquis ; lateralibus sublongis subcurvisque ; margarita alba et vald6 iridescente. 



Shell plicate, elliptical, roughly harrowed, compressed, very inequilateral, trian- 

 gular behind, regularly rounded before; valves somewhat thick; beaks slightly 

 prominent, very much compressed, with beautiful divaricating folds at the tips ; 

 epidermis yellowish-olive and very rugose; cardinal teeth very small, compressed, 

 oblique; lateral teeth rather long and somewhat curved; nacre white and very 

 iridescent. 



Ilab. — Bengal, W. A. Haines. 



My cabinet and cabinet of Mr. Haines. 

 Diam. -4, Length -8, Breadth 1-3 inch. 



Shell folded, elliptical, roughly harrowed, compressed, very inequilateral, biangular 

 behind and regularly rounded before ; substance of the shell somewhat thick ; beaks 

 slightly prominent, very much compressed, with beautiful, small divaricating folds 

 at the tips ; ligament small and light-brown ; epidermis yellowish-olive, very rugose 

 and with distant marks of growth ; umbonial slope slightly raised and obscurely 

 bicarinate ; posterior slope minutely plicate slightly raised, furnished with two dark 

 lines from the beaks to the posterior margin; cardinal teeth small, compressed, 

 oblique and crenulate ; lateral teeth rather long and somewhat curved ; anterior 

 cicatrices distinct, rather large and well impressed; posterior cicatrices confluent 

 and slightly impressed; dorsal cicatrices under the plate posterior to cardinal tooth; 

 cavity of the shell very shallow ; cavity of the beaks very shallow and angular ; 

 nacre white, satin- like and very iridescent. 



Bemarks. — This little species is very nearly allied to fi7iurtleffianus (nobis) and 

 gratiosus, Phili., but it is more compressed and more oblique ' than either of them, 

 and it has a transverse crimpling, which is very remarkable. The posterior slope is 

 oblique, and terminates in rather a sharp angle. In both the specimens before me 

 there is a disposition to have a curve in the plate between the cardinal and lateral 

 teeth. The anterior lobe of the cardinal in the left valve is much higher and larger 

 than the other lobe. The nacre is of remarkable richness. 



Mtcetopus emarginatus. PI. 50, fig. 305. 



Testa tevi, transversissima, coinpressa, einarginata, ad latere planulata, antice inflata, postice ampliatiit 

 et compressa,-; valvulis pertenuibus, diaphinis ; natibus parvis, prominulis; epidermide luteo-cornea 

 valde striata, nitida, eradiata; margarita, caerulco-alba et valde iridescente. 



