54 



IJXIO. 



f OBLONG. 



*fulvus. Lea. Han. 

 TJnio icterinus. Con. 



^rufusculus. Lea. 



*Gibbesianus. Lea. 



*sordidus. Lea. 



*Dariensis. Lea. Chenu. 



*Congara3us. Lea. Chenu. Han. 



*inerus. Lea. 



*C]iarruanus.' D^Orl. 



rliuacoicus. D'OrS. Von Mar. 



^neglectus. Lea. 



*subplaii'us. Con. 



^'manulDius. Oould? 



*declivis. Say. Desh. Kilst. Han. 

 TJnio geometricus? Lea. 

 Unio excultus. Con. 



*paludicokis. Gould. 



*Blandingianus. Lea. Kilst. 

 Unio rivicolus. Con. 



*quadratus. Lea. 



OBLONG. 



*depressus. Lam. Less. Chenu. Kiist. 

 Han. 

 Unio Bahnnensis.^ Con. 

 Unio ambiguus. Phil. 

 Unio profugus. Gould. 

 Unio Angasi. Reeve. (No. 282.)' 



angustus. Lam. Han. 

 *cacao. Lea. 

 *niodestus. Fer. 

 *suavidicus. Lea. 



fameliciis. Gould. 

 *Couc]iiaiLus. Lea. 



*litoralis. Drop. Lam. Mill. Pfeif. 



Mossm.^ Des Moul. Grat. JBrard. 



Desh. Cuv. Maton and Racket. 



Bouil. Gras. Bronn. More. Mer- 



met. Gassies. Goupil. Dupuy. 



Puton. Poller. Graells. Mouss. 



Han. Caill. 

 Unio crassus. Nil. Phili. Menlce. 



Rossm. Moq. 

 Unio hrevialis. Lam. 

 Unio nana. Lam. Dup. Bourg. 

 Unio suitetragona. Mich. Hup). 



Merm. Graells. Gras. 

 Unio ijicurvus. Lea. Chenu. 

 Unio Pianensis. Farines. Dup. 



Graells. 

 Unio granosus. Schum. 



' The two specimens sent to me by M. D'Orbignj' are much smaller than the adult figured b}' him 

 in Voy. Am. Mer., and although very like delodontits, Lam., are difTerent in outline and in some minor 

 characters. 



^ I am disposed to believe that this is only a variety of decUvis, Say. I have specimens from Texas 

 ■which indicate this. 



' I do not find this or declivis in Mr. Say's Synonymy. He has, however, priority. 



* In a subsequent paper, Jl. A. N. S., vol. ii. p. 295, Mr. Conrad says that, in referring the shell to 

 depressus, Lam., I have committed "an oversight." I do not admit this, but consider myself to be cor- 

 rect, having long had a specimen of U. dej^ressus in my possession, and having seen it frequently in 

 various cabinets in Euroije. 



^ Mr. Reeve cites my MS. for this name. I have no recollection of it. 



" Rossmtissler, Iconographie, vol. iii. p. 36, describes a variety under the name of umbonatus. 



