82 DESCRIPTION OF NEAV 



and shallow ; cavity of the beaks very small ; nacre bluish and irides- 

 cent. 



Remarks. — I procured this remarkably compressed ^nodonta from 

 Mr Warren, of Boston. Its habitat, unfortunately, was not known. 

 It may be distinguished from all the other species with which I am 

 acquainted by its compressed and slender form. 



Iridina cgelestis. Plate XXII. fig. 70. 



Testa latissima, subcylindracea, loEvissimd, valdh incBquilaterali ; valvuUs tenuibus ; natibus 

 prominulis ; epidermide polild, tenebrosd ; margaritd carulea et iridescente. 



Shell very broad, subcylindricai, very smooth, very inequilateral ; valves thin ; beaks 

 somewhat prominent ; epidermis polished, very dark ; nacre bluish and iridescent. 



Hab. Africa. 



My Cabinet. 



Cabinet of Dr Jay. 



Diam. -7, Length 1-1, Breadth 3-4 inches. 



Shell very broad, subcylindricai, very smooth, very inequilateral, 

 straight on the dorsal margin, rounded before and angular behind ; sub- 

 stance of the shell thin and delicate; beaks somewhat prominent, and 

 apparently without undulations at the tip; epidermis highly polished, 

 nearly black on the anterior, posterior and inferior portion of the valves, 

 obsoletely rayed ; cicatrices scarcely visible ; cavity of the shell rather 

 deep ; cavity of the beaks very small ; nacre bluish, with a tint of pur- 

 ple on the anterior portion, very iridescent. 



Remarks. — The first specimen of this shell which came under my 

 notice I purchased from a dealer in New York, who informed me it 

 came from Africa. For a second specimen, I am indebted to Dr Jay, 

 who gave me the same habitat. It was sent to him under the impres- 

 sion of its being the "J/M/e/" of Adanson. By a comparison with 

 Adanson's figure, it will be at once observed to differ from it entirely 



