396 NEW EXOTIC UNIONIDiE. 



swollen ; epidermis shining, very dark-green or blackish, obsoletely rayed or with- 

 out rays ; nacre within the cavity inclined to rose color and very iridescent. 

 Hob. — Upper Amazon, Brazil, C. M. Wheatley. 

 My cabinet and cabinet of C. M. Wheatley. 

 Diam. -9, Length 1-4, Breadth 3*1 inches. 



Shell smooth, transverse, somewhat oblique, rather inflated, very inequilateral, 

 somewhat biangular behind and rounded before; substance of the shell rather thick, 

 thick on the dorsal margin ; beaks somewhat raised, swollen, apparently without 

 undulations at the tips ; ligament long and thin ; epidermis shining, very dark-green, 

 almost black, obsoletely rayed, or without rays, with distant marks of growth ; 

 umbonial slope slightly raised and flattened ; posterior slope blackish, rather nar- 

 row, depressed, with three indistinct, raised lines on each valve, from the beaks to 

 the posterior margin ; anterior cicatrices distinct and well impressed ; posterior cica- 

 trices confluent, large and slightly impressed ; dorsal cicatrices scarcely visible ; 

 cavity of the shell rather shallow ; cavity of the beaks very shallow and rounded ; 

 nacre within the cavity inclined to rose color and very iridescent. 



Remarks. — Several specimens were kindly submitted to me by Mr. Wheatley, 

 and I was at first disposed think they might be a variety of Wheatleyi (nobis), or 

 solidula, Deville and Hupp6 ; but it is a larger species than the first, not quite so 

 thick in the nacre, nor of so brilliant a nacre, and in the epidermis they differ very 

 much, — the Amazcmensis being nearly black, while the other is cinnamon-red. In 

 outline it is very near to solidula ; but that species is described as being deep brown, 

 while this is a deep green and is more oblique. Still it may prove to be but a 

 variety, when complete suites are observed. The beaks of none of the specimens 

 before me are entirely perfect — they may have small undulations at the tips, but 

 there is no appearance of any in these specimens. When young, the epidermis will 

 be found probably of a dark green and with rays, as the older ones show a slight 

 inclination to rays. The sinus at the end of the ligament has the usual triangular 

 form of the South American species. 



Anodonta Moricandii. PI. 49, fig. 303. 



Testa lsevi, oblique quadrata, subinflata, ad latere planulata, valde inaequilaterali, postice obtuse angu- 

 lata et hiaiite ; antice oblique rotundata et valde hiante; valvulis tenuibus, diaphinis ; natibus sub- 

 prominentibus ; epidermide luteo-oliv&, polita, obsolete radiata ; margarita caeruleo-alba et valde" 

 iridescente. 



Shell smooth, obliquely quadrate, slightly inflated, flattened at the side, very in- 

 equilateral, obtusely angular behind, obliquely rounded before and very much gaping 

 behind and before; valves very thin, semitransparent ; beaks somewhat prominent; 



