UXIO, 



57 



5 ' 



STJBHOTUND. 



Unio catillus} Con. Kilst. 

 Unio cuneus? Con. 



*ornatus. Lea. 



*seminigatus. Lam. Menke. Chenu. 



*Emesaensis. Lea. 



WIDE. 



*Shepardianus. Lea. Con. Kilst. 

 Chenu. Han. 



Bensonii. 2 Lea. 

 An. soleniformis. Ben. 

 Spatha soleniformis. Ben. (In lit.) 



Duttonianus. Lea. Chenu. 



*folliculatus. Lea. Chenu. Han. 



*rectus. Lam. Sh. & Eat. Swain. 



Adams. Han. Dekay. Potier. 



Kilst. Chenu. 

 Unio prselongus. Bam. Hild. 

 Unio arquatus? Con? 

 Unio recta. Valen. 

 Unio Sageri? Con. 



WIDE. 



Unio lejirosus. Miles. 

 Mya prselonga. Wood. Eat. 

 Ligumia recta. Swain. 

 Eurynea prselonga. Stimpson. 

 (Agass. MSS.) 



*strigosus. Lea. Chenu. 



*perstriatus. Lea. 



*Siamensis. Lea. 



*Poeyanus. Lea. 



*Popeii. Lea. 



*angustatus. Lea. Con. Chenu. Han. 



*sublatus. Lea. 



*latus. Lea. 



*verutus. Lea. 



*Ocmulge'ensis. Lea. 



*dactylus. Lea. Chenu. 



*lanceolatus. s Lea. Chenu. Desh. Han. 



1 The late Dr. E. E. Griffith had in his collection a shell marked catillus, he thought by Mr. Conrad 

 himself, but which I think was only a variety of obliquus, Lam.; certainly it is not the species figured by 

 Mr. Conrad. In a letter from Dr. Ward in 1836, he says, " U. catillus runs into coccineus, so that Mr. 

 Conrad would be puzzled to part the species in my collection. They arc only varieties of the same species.'' 



2 A single old valve (diam. .7, length 1.5, breadth .6 inches) was submitted to me, with a complete 

 young specimen 2.3 inches wide, by W. H. Benson, Esq., of London. The old valve is imperfect along 

 the dorsal margin, but still there may be observed imperfect cardinal and lateral teeth. In the young 

 specimen, the lateral teeth, while being very delicate and circular, are perfectly well defined, being double 

 in the left and single in the right valve. As Mr. Benson's name (soleniformis, Jl. Asiatic Sec., vol. v., p. 

 750, 183G) has already been used for a Unio, I propose Bensonii for it in honor of the discoverer, who 

 has done so much for the Natural History of the East of Asia. 



3 1 have a deformed rectus so exactly like the figure given by Mr. Conrad that I cannot help thinking 

 they are the same. 



4 Mr. Conrad's figure so nearly resembles the male specimens of U. rectus, from Green Baj-, in my 

 cabinet, that I am persuaded the Sageri will not prove to be a distinct species. Drs. Kirtland and Ward, 

 and Judge Tappan, consider it a variety of gibbosus of Barnes. In Mr. Conrad's Synopsis (1852) he 

 seems to have abandoned the name, as he has not inserted it there. 



5 M. Deshayes (2d edit. Lamarck) doubts if lanceolatus be not the young of anodontoides, "of Say.'' 

 (Anodontoides was not described by Mr. Say, but by myself.) The first has been found only in the waters 

 east of the Alleghany Mountains, the last onl}- in the western waters. There cannot be a doubt of their 

 being distinct species. In size they differ altogether. 



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