NO. 1205. SYNOPSIS OF THE NAIADES— SIMPSON. 637 



(Group of Anodonta woodiana.y 



Shell oval, inflated, sometimes narrowed in front, pointed behind, 

 and often a little produced at the posterior base, slightly winged in the 

 post-dorsal region ; beaks full, sculptured with numerous strong con- 

 centric ridges, which are either straight in the center of the disk or 

 slightly doubly looped. There is often a faint posterior ridge, which 

 may be double, making the shell feebly biangulate behind; dorsal 

 scars one or two under the beaks; muscle scars irregular. 



Animal with the gills large, equal in size, rounded below, free the 

 greater part of their length from the abdominal sac, somewhat 

 wrinkled ; marsupium occupying the entire outer gills, forming thick 

 brown pads when filled; palpi large, subelliptical, free from the mantle 

 a long way; mantle having a wide, thickened edge; branchial oj)ening 

 crowded with dark papillas; anal opening with no papilhie, but having 

 purple ridges inside ; superanal opening closed nearly its whole length.^ 



f ANODONTA WOODIANA Lea. 



*Symphynota woodiana Lea, Tr. Am. Phil. Soc, V, 1834, p. 42, pi. v, fig. 13 ; * Obs., 



I, 1834, p. 154, pi. A^, fig. 13. 

 ^Margarita {Anodonta) woodiana Lea, Syn., 1836, p. 48; 1838, p. 29. 

 *Anodon ivoodiana Catlow and Reeve, Conch. Nom., 1845, p. 68. — *.Sowerby, 



Conch. Icon., XVII, 1870, pi. xxxvi, fig. 149. 



* Anodonta woodiana Hanley, Test. Moll., 1842, p. 215 ; * Biv. Shells, 1843, p. 215. — 



*H. and A. Adams, Gen. Eec. Moll., II, 1857, p. 503. — *Clessin, Conch. 



Cab. Ano., 1875, p. 146, pi. xlviii, figs. 1, 2. 

 *Margaron {Anodonta) woodiana Lea, Syn., 1852, p. 47; 1870, p. 75. 

 iSymphynota magnifica Lea,-' Tr. Am. Phil. Soc, V, 1834, p. 42, pi. v, fig. 14 ; Obs., 



I, 1834, p. 155, pi. V, fig 14. 



* Margarita {Anodonta) magnifica Lea, Syn., 1836, p. 48; 1838, p. 29. 



* Anodonta magnifica Hanley, Test. Moll., 1842, p. 215; Biv. Shells, 1843, p. 215.— 



*H. and A. Adams, Gen. Rec. Moll, II, 1857, p. 503.—* Chenu, Man., 1859, II, p. 



146, fig. 719. — * SCHRENCK, Reis and F. Am. Lande., II, 1867, p. 718, pi. xxviii, 



figs. 1, 2.— *PiETEL, Conch. Sam., Ill, 1890, p. 181. 

 * Anodon magnifica Catlow and Reeve, Conch. Nom., 1845, p. 67. — Sowerby, 



Conch. Icon., XVII, 1870, pi. xxv, fig. 96. 

 *Margaron {Anodonta) magnifica Lea, Syn., 1852, p. 47; 1870, p. 75. 

 ^% Anodonta aurata Kuster, Conch. Cab. Ano., 1853, p. 30, pi. vi, fig. 2. 



^Fischer has made a subgenus Pteranodon (Man. Conch., p. 1003) for A. magnifica, 

 but I do not see any need of giving it and the related species any higher rank 

 than that of a group. The shell and animal differ but little from those of other 

 Anodontas.^ 



^A group closely agreeing in general characters, but having enormous individual 

 variation. Pere Heude has bestowed specific names on a great number of forms, 

 most of which are, I think, merely mutations of Lea's woodiana. Fortunately the 

 U. S. National Museum possesses in the Morelet collection a large series of author's 

 specimens, and the excellent figures in the Conchyliologie Fluviatile Nanking 

 enable me to straighten out this difficult group to some extent. 



^Larger and rather more finely developed than A. ivoodiana, but the large series 

 of material I have examined absolutely connects the two. 



