1058 



NAIADS. 



NAIADS. 



1054 



** Non-Symphynote. 

 Ex. Unto Pictorwm, common in our English rivers. [CONCHIFERA.] 



Unio Pictoriun. From" a young specimen. 



In Mr. Garner's 'Memoir on the Anatomy of the Lamellibranchiate Con. 

 chifera ' (pi. xx.) the ova of Unio Pictorvm from the ovaries and branchice are 

 represented (18th of an inch focus) ; also the valve of a young Unio, showing 

 that its nucleus is of the game shape as the valves of the animals found in the 

 branchicr. 



2. Sub-Genus. Margaritana. Having One Tooth (Cardinal). 



*** Non-Symphynote. 

 Ex. Alasmodonla itndalata. (Say). 



Alasmodonta undulata. 



Symphynote. 

 Ex. Alatmodonta complanata. (Barnes.) 



Alatmoctonta complanata, 

 3 Sub-Genus. Dlpiai. Having a Linear Tooth under the dorsal 

 margin - Symphynote only. 



Ex. IHptat plicatui. (Leach.) 

 4. Sub-Genus. Anodonta. Having no Teeth. 



* Symphynoto. 

 Ex. Symphynota magnifiw. (Lea.) 



** Non-Symphynote. 

 Ex. Anodonta flumatUu (Mytilus fluviatilis of Solander, Dillwyn, 

 &c. ; Anodonta, catarracta of Say). 



Plalirie. (Lea.) 

 1. Sub-Genua. Iridina. Having a Crenulate Dorsal Margin. 



Non Symphynote. 

 x. Iridina exotica. [ConcHACEA.] 



Dlpsas plicatus. 



i ota magnijtea. 



Anodonta fluviatilis. 



2. Sub-Genus. Spatha. Having the Dorsal Margin Non-Crenulate. 



Non-Symphynote. 

 Ex. Iridina Nilotica. (Sowerby.) 



Iridina Nilotica. 



Plicate Shells. 

 Ex. Unio plicatm. (Lesueur.) 



Nodulous Shells. 

 Ex. Unio putliilosus. (Lea.) 



Smooth Shells. 

 Ex. Unio complanalus (Unio pnrpnrent, Say). 



