30 



SYNOPSIS OF 



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Anodontites cygnea.f Pair. 

 Anodontiles aimtiiia. Poir. 



s 



*Oregonensis. Lea. 



*Pepiniana. Lea. 

 *fragilis. Lam. 



uniopsis. Lam. 



Chaiziana4 Rang. 



*undulata. Say. 



Anodoii*iugosus. Swain. 

 Anodonta Pennsylvanica. Lam. 



*Wardiana. Lea. 

 A. virgata. Con. 



*edentula. Lea. 



Alas, edenliila. Say. 



Anodon. areolatus. Sioain. Coop. 



*pavonia. Lea. 



*limnoica. D^Orb. 



tiigona.§ Spix. 



purpurea. Valen. 



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OVAL. 



*Ferussaciaua. Lea. 



*saImonia. Lea. 



*iiicerta. II Lea. 

 imbecillis ] Say. 



*Newtonensis. Lea. 



*fluviatilis. Lea. 



Myt. fluviatilis.^ Soland. Dill. 



Wood. 

 Myt. illitus. Soland. 

 An. cataracta. Say. 

 An. marginata. Say. 

 An. implica(a'? Say. 

 An. teres. Con. 



*Mortoniana. Lea. 



An. Chiquitana. D^Orb. 



^glauca.ff Valen. 

 An. glauca. Lam. 



*ovata. Lea. 



*plana. Lea. 



An. declivis. Con. 



[ *decora. Lea. 



t On the authority of Des Moulins. 



X M. Rang informs us that this species has the singular power of maintaining its vitality in the desiccated 

 marshes of Africa, through six months of the burning sun of that region ; and that he had a specimen sent to him 

 in Paris, which was killed nearly thirteen months after it had been taken from its native bed, having occasion- 

 ally been dipped in water for an hour or two only. He also mentions that the Iridina rubens is found with the 

 Chaiziana in the Senegal, and possesses the same peculiarities of remaining in a state of torpidity during the 

 season of great heat. 



§ Ferussac considered trigona as the same with crassa of Swainson. The two figures, however, appear 

 to me to be too diffeient to be considered the same. 



II Dr Kirlland informs me, that a specimen of this shell, which he showed to Mr Say, was considered by 

 Mr S. to be his imbecillis. If this be so, Mr Say's name is entitled to precedence. I have never seen the shell 

 described by Mr S. as imbecillis. 



^ See note on Jln. cygnea, page 137. 



tt The figure of this shell resembles some individuals of Myt.fluviatHis, Soland. (Say's An. cataracta), but 

 is straighter on the superior margin. In this character it resembles the trapezialis. The observations of Barnes, 

 being made when little was known of this genus, cannot now be admitted. 



