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Art. VI. — New Unionidce of the United States. 

 By Isaac Lea, LL. D. 



In my last paper, which was published in the Journal of the Academy, there were 

 described at length, forty-one new indigenous species of the Unionidw, many of which 

 had the advantage of the diagnosis of the soft parts. I now offer to the Academy, in 

 this paper, carefully made descriptions of thirty-eight species, which include a few 

 diagnoses of the soft parts of old species not before examined anatomically, and of 

 which I have given carefully made figures. All the new species of my own in this 

 paper are from Georgia, and are referred to in the Proceedings of the Academy, where 

 they have been simply characterized. We have by no means exhausted Georgia as 

 yet. I have prepared diagnoses of the soft parts of many heretofore described, and 

 new ones are almost constantly being received by me from various friends in the 

 Southern States, who are greatly interested in their development. These will appear 

 from time to time in our Proceedings and in our Journal. 



The descriptions and figures of the soft parts in this paper will be found to be 

 important. That of Unio rnultiplicatus (nobis) represents the anomalous character 

 of the female of this large and multiplied species, so common in the valley of the 

 Ohio, with her distended branchial uterus occupying the four leaves of the branchise, 

 charged with probably three or four millions of embryonic shells ready to be hatched. 

 The singularly formed plicate branchial uterus of Woodwardianus (nobis) and phase- 

 olus, Hild., will also attract the attention of the zoologist. 



Unio bulbosus. PL 21, fig, 75. 



Testa laevi, obliqua, valde inflata, valde insequilaterali, postice obtuse angulata ; valvulis crassis, antice 

 crassioribus ; natibus tumidis et elevatis; epidermide nigricante, micante, eradiata; dentibus cardin- 

 alibus subgrandibus, subpyramidatis crenulatisque ; lateralibus curtis, subcrassis subrectisque ; mar- 

 garita, vel alba vel salmonis colore tincta et iridescente. 



Shell smooth, oblique, very much inflated, very inequilateral, obtusely angular 

 behind ; valves thick, thicker before ; beaks swollen and elevated ; epidermis blackish, 

 shining, without rays; cardinal teeth rather large, somewhat pyramidal and crenu- 

 late; lateral teeth short, rather thick and nearly straight; nacre either white or 

 salmon colored and iridescent. 



Poc. Acad. Nat, Sci., 1857, p. 172. 



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