54 



UNIO. 



c 



E- 



o 



f OBLONG. 



*fulvus. Lea. Han. 



XJnio icterinus. Con. 



*rufusculus. Lea. 

 *Gibbesianus. Lea. 

 *sordidus. Lea. 

 *Dariensis. Lea. Chenu. 

 *Congarseus. Lea. Chenu. Han. 

 *merus. Lea. 

 *CL.arruanus. 1 D'Orb. 

 rhuacoicus. D'Orb. Von Mar. 

 *neglectus. Lea. 

 *subplarms. Con. 

 *manubius. Gould? 



*declivis. Say. Desk. Kilst. Han. 

 Unto geometricus? Lea. 

 JJnio excultus. Con. 



*paludicolus. Gould. 



*Blandingianus. Lea. Kilst. 

 JJnio rivicolus. Con. 



*quadratus. Lea. 



' OBLONG. 



*depressiis. Lam. Less. Chenu. Kilst. 

 Han. 



JJnio Balonnensis. 1 Con. 



JJnio ambiguus. Phil. 



JJnio profugus. Gould. 



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



angustus. Lam. Han. 

 *cacao. Lea. 

 *modestus. Fer. 

 *suavidicus. Lea. 



famelicus. Gould. 

 *Couchianus. Lea. 



*litoralis. Drap. Lam. Mill Pfeif. 



Possm. 6 Pes Moul. Grat. Brard. 



Pesh. Cuv. Maton and Packet. 



Bouil. Gras. Bronn. More. Mer- 



met. Gassies. Goupil. Pvpuy. 



Puton. Potier. Graells. Mouse. 



Han. Caill. 

 JJnio crassus. Nil. Phili. Menhe. 



Rossm. Moq. 

 JJnio brevialis. Lam. 

 JJnio nana. Lam. Dup. Bourg. 

 JJnio subtetragona. Mich. Dup. 



Merm. Graells. Grae. 

 JJnio incurvus. Lea. Chenu. 

 JJnio Pianensis. Farines. Dup. 



Graells. 

 JJnio granosus. Schum. 



1 The two specimens sent to me by M. D'Orbigny are much smaller than the adult figured by him 

 in Voy. Am. Mer., and although very like delodontus, Lam., are different in outline and in some minor 

 characters. 



2 1 am disposed to believe that this is only a variety of declivis, Say. I have specimens from Texas 

 which indicate this. 



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



4 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. depressus in my possession, and having seen it frequently in 

 various cabinets in Europe. 



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



6 Rossmiissler, Iconographie, vol. iii. p. 30, describes a variety under the name of umbonatus. 



