THE FAMILY NAIADES. 



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IV. SUBGENUS ANODONTA. 



TRIANGULAR. 



*Wahlamatensis. Lea. 



OVAL. 



*magnifica. 



Lea. 





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Symp. magnifica. Lea, Trans. Am. 

 P. S. 



*Woocliana. Lea. 



Symp. Woodiana. Lea, Trans. Am. 

 P. S. 



*BenecIictensis. Lea. 



Symp. Benedictensis. Lea, Trans. 

 Am. P. S. 



*Nuttalliana. Lea. 



OBOVATE. 



*crispata. Lam. 



rOVAL. 



*cygnea.t Drap. Lam. Crouch. Blain. 



Pfeif. Turt. Des Moul. Flem. 



Grat. Bouil. 



Myt. cygneus. Gmel. Chem. SchrO. 



Dill. Miihl. Monta. Mat.X 



Shep. Tur. 



Myt. anatinus. Gmel. Chem. SchrO. 



O 

 Q 

 O 



O 

 15 



OVAL. 



/Sc/mm. ^ooc^. Monta. Tur. Dill. 



Mat. 

 Myt. stagnalis. Gmel. Base. Dill. 



Sow. 

 Myt. fluvialilis.§ Gmel. 

 Myt. fucatus. Dill. 

 Myt. Zellensis. GmeZ. >S^cArO. Bosc. 

 Myt. Avonensis. Monta. Wood. 



Ed. Encyclopcedia. 

 Myt. radiatus.y JViw/iZ. SchrO. 

 Myt. incrassatus. /S/icp. 

 Myt. macula. Shep. 

 An. anatina. Z/ffm. Dill. Drap. 



Sow. Pfeif. Flem. Grat. Des 



Moul. Bouil. 

 An. sulcata. Lam. 

 An. dentiens. Menke. 

 An. intermedia. Lam. Pfeif. Bouil. 

 An. variabilis. (Var. b.) Drap. 

 An. cellensis. Pfeif. 

 An. ventricosa. Pfeif. 

 An. ponderosa.^y P/ei/. 

 An. paludosus. Tur. 

 An. grossa. Z'eig-. 

 An. compressa?ff Zeig. 

 An. obvolutalff Z^e/g. 

 An. spuria. Count Yoldrs Letter. 

 An. proboscidalis. Zeig. 

 An. piscinalis. JWZ. 



t I have, after a good deal of consideration and examination of my specimens, and the figures in (he nume- 

 rous works describing the Naiades, satisfied myself that ^n. cygnea and An. anatina are not specifically dis- 

 tinct. If the observation of M. Poiret, that the first is viviparous and the last oviparous, be correct, then they 

 should be certainly separated. I feel perfectly persuaded, however, that he must be in error. Turlon, 

 in his recent work on the Land and Fresh Water Shells of Great Britain, says he is " inclined to think that all 

 our supposed species of this genus may be justly resolved into one." 



X /3 of Maton and Racket (Lin. Soc. Trans., Vol. IV.) is evidently, judging from the figure, Unio litoralis. 



§ Gmelin states this shell to be from the fresh waters of Europe, and allied to Anatina. If this be true, 

 there cannot be a doubt of its being the same with cygnea. The Jluviatilis of Solander and Dillwyn is said to 

 be from North America, and is no doubt the cataracta of Say. 



II On the authority of Dillwyn. 



^ This and the grossa are certainly very different in aspect from the cygnea, Lam., being more ponderous 

 and less produced behind. This difference may, hov/ever, be effected by locality. Should it prove constant, 

 ponderosa ought to be considered a distinct species, and I am much disposed to think that such will prove to 

 be the fact. 



tt On the authority of Ferussac. 

 VI. 2 K 



