24 



U NIO. 



f ("triangular. 



*donaciformis. 1 Lea. Desk. Chenu. 



*zigzag. Lea. Eat. Desk. Chenu. 

 *heterodon. Lea. Con. J)esh. Ling. 



*penitus. 2 Con. 



*Estabrookianus. Lea. 



*securis. Lea. Eat. Desk. Chenu. 

 Unto depressa* Raf.; but not of 



Lam. 

 TJnio lineolatus. Say. 



*abacus. Hald. 



*camelus. 4 Lea. 



*compressissiraus. Lea. 



*ovatus. Say. Lam. Bar. Valen. 

 Eat. Eild. Con. Kttst. 

 TJnio ventricosus. Eesh. 

 TJnio subovatus. Eesh. 

 TJnio occidens. Eesh. 

 JEglia ovata. Sivain. 



*satur. Lea. 



*subovatus. 5 Lea. Chenu. 



TRIANGULAR. 



*crassidens. 6 Lam. 



TJnio cuneatus. Bar. Eat. Eild. 



TJnio niger? Raf. 



TJnio niger. Con. Kilst. 



*incrassatus. Lea. 



*Forbesianus. Lea. 



*gibber. Lea. Chenu. 



*pumilis. Lea. Chenu. 



Orbignyi. Eeville and Euppe. 



*rubiginosus. Lea. Eesh. Chenu. 

 TJnio flavus. Con. Kttst. 

 TJnio cerinus. Con. Kiist. 



*succissus. Lea. 



*Bigbyensis. Lea. Chenu. 



*maculatus. 7 Con. 



*Barnesianus. Lea.. Chenu. 



*cuneolus. Lea. Chenu. 



*pileus. Lea. Chenu. 



1 I have expressed my doubts, Transactions of the American Philosophical Society, vol. iv. p. 84 (p. 94 in 

 "Observations on the Genus TJnio," &c), if this be more than a fine variety of zigzag (nobis). Mr. Say gives it 

 as a synonyme to nervosus, Raf., and Mr. Conrad as truncata, Raf. Prof. Kirtland thinks this may be the female 

 of zigzag. 



3 I received from Judge Tait, of Alabama, in 1830, several specimens of this species, but they were not suffi- 

 ciently perfect to induce me to publish them. Mr. Conrad does not mention the rays, a very peculiar character of 

 which is their being clotted somewhat like those of securis (nobis), but in a lighter manner. 



3 Mr. Conrad makes dcpressa, Raf., ellipsaria, Raf, and securis (nobis), synonymous with lineolata, Raf. Mr. 

 Say does the same, with the exception of ellipsaria, which he considers distinct ; while Mr. Rafinesque himself 

 places lineolata and ellipsaria in different subgenera ! ! 



4 I am much disposed to think this a variety of phaseolus, Hild. Dr. Kirtland considers it such in his Ohio 

 Reports. 



5 Mr. Say makes " ventricosus, Bar., occidens (nobis), subovatus (nobis), (var.), and capax, Green (var.)," 

 synonymous with cardium, Raf. In my opinion, they form at least three, perhaps four, distinct species. 



6 Crassidens, Var. a, Lam., is trapezoides (nobis). 



7 Perfect specimens of Unio Ravenelianus (nobis) look so much like maculatus, that I am disposed to think, 

 when many specimens of both are examined, they will prove to be the same species. Ravenelianus has precedence. 



