U X I O . 



K 



C 

 ' 







C 



IB 



SUBROTUXD. 



ZTm'o catiUus} Con. K'dst. 

 Unio cuneusf Con. 



*ornatus. Lea. 



*semirugatU8. Lam. Menke. Chenu. 



*Emesaensis. Lea. 



WIDE. 



*Shepardianus. Lea. Con. K'dst. 

 Chenu. Han. 



Bcnsonii. 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. Poticr. 



Kust. Chenu. 



Unio preelonfjus. Barn. Hild. 

 Unio arquatus? Con. 3 

 Unio recta. Valen. 

 Unio Sageri.* Con. 



SC 1 5 

 > I v. 



WIDE. 



f'/'i'<> leprosut. Miles. 

 Afya praelonya. Wood. Eat. 

 Li'jumia recta. Swain. 

 Eurynea prielonya. Stimpson. 

 (Agass. MSS.) 



*strigosus. Lea. Chenu. 



*pcrstriatus. Lea. 



*Siamensis. Lea. 



*Poeyanus. Lea. 



*Popeii. Lea. 



*angustatus. Lea. Con. Chenu. II 



*sublatus. Lea. 



*latus. Lea. 



*verutus. Lea. 



*0cmulge'ensis. Lea. 



*dactjlus. Lea. Chenu. 



*lanceolatus. 5 Lea. Chenu. Desh. IIa. 



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

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

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

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



- 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 perfectlj- well defined, being double 

 in the left and single in the right valve. As Mr. Benson's name (sol<'iiif->nn!.<, .11. Asiatic Sec., vol. v.. p. 

 YoO, 1836) 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. 



8 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. recta*, fmm Green Bay. in my 

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

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

 seems to have abandoned the namej as he has not inserted it tliero. 



5 M. Deshnyes ('2d edit. Lamarck) doubts itlani-1-nlti/u* bo not the young of amodt . { Say." 

 (A mtdontoides was not described by Mr. Say. but by myself.) The first has l>een found only in the waters 

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

 lioing distinct species. In size the}' differ altogether. 



15 



