I 



SUBROTUND. 



Variabilis. Lea. D'Orb. 



My a variabilis. 1 Mat. Wood. Dill. 

 Diplodon rotundus. Spix. 

 TJnio rotundus. Wag. 



*personatus. 2 Say. Kiist. 

 TJnio capillaris. Lea. 



*retusus. 3 Lam. Con. Menke. Kiist. 

 TJnio torsa. Raf. Eat. Potier. 

 TJnio obtusa. 4 Cuvier. 

 TJnio cordatus (female). Kiist. 



*ebenus. Lea. Chenu. 



TJnio mytiloides. Con.; not Raf. 

 TJnio obliquus. Con. Kiist. 

 TJnio Grouldianus. Ward. 



*Lesueurianus. Lea. Chenu. 



*nucleopsis. Con. 



*Kirtlandianus. i Lea. 



*pilaris. Lea. Chenu. 



*dollabelloicles. Lea. Chenu. 



' SUBROTUND. 



*subrotundus. Lea. Chenu. 

 TJnio politus ? Say. Kiist. 

 TJnio brevialisf Crouch.. 

 TJnio politus. Con. 



*coccineus. Lea. Chenu. 



TJnio coccineus. Dr. Hildretlis 



Letter. 

 TJnio coccineus. Con. 



TJnio catillus. 6 Con. Kiist. 



TJnio cuneus? Con. 



WIDE. 



*Shepardianus. Lea. Con. Kiist. 



Duttonianus. Lea. Chenu. 



*folliculatus. Lea. Chenu. 



*rectus. Lam. Eat. Swain. Adams. 

 Dekay. Potier. Kiist. 

 TJnio prselongus. Bam. Hild. 

 TJnio recta. Valen. 

 TJnio Sageri. 7 Con. 

 My a prselonga. Wood. 

 Eurynea prselonga. Stimpson. 

 (Agass. MSB.) 



1 The figure of this shell in the Lin. Soc. Trans., vol. x., although so much smaller a shell than Paranensis 

 (nobis), is so much like it that I should not be surprised if they should prove to be the same. Lamarck considered 

 this the same with his Syria corrugata. 



(Since the publication of this note, I have received, from M. Moricand, a suite of specimens of Paranensis, 

 which indicate, unquestionably, a distinct species. The beaks of rotundas, Wag., have not the strong folds on the 

 beaks, while the Paranensis has many elevated radiations from the beaks. The outline too of the former is more 

 orbicular.) 



2 Prof. Kirtland thinks this is the female of pileus (nobis), but I am not of this opinion. 



3 M.' Deshayes thinks this is incurvis, Say. I do not know where Mr. Say published a shell under that name. 

 * In the recent edition of Cuvier Reg. An., by his pupils, there is a beautiful figure of U. retusus, Lam., under 



the name of U. obtusa, Say. I am not aware that Mr. Say described a Unio under that name. The retusus, Lam., 

 is a common, well-known, and perfectly distinct species. 



5 Prof. Kirtland, in his Ohio Report, expresses his opinion of this being only a very flat variety of subrotundus 

 (nobis). 



6 The late Dr. R. 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. 



7 Mr. Conrad's figure so nearly resembles the male specimens of U. rectus, from Green Bay, 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. 



