630 PROCEEDINGS OF THE NATIONAL MUSEUM. vol xxii. 



ANODONTA COARCTATA Anton. 



*Avodonta coarctata Anton, Verz. der Couch., 1839, p. 16. — *Troschel, Arch, fiir 

 Nat., Xr, 1845, Pt. 2, p. 323.— *Kuster, Conch. Cab. Auo., 1853, p. 34, pi. viii, 

 fig. 2.— *B. H. Wright, Check List, 1888.— ^ P^tel, Conch. Sam., Ill, 1890^ 

 p. 177.— * Fischer and Crosse, Miss. Sci., Pt. 7, II, 1894, p. 519. 



"Anodoyita chapalensis Crosse and Fischer, J. de Conch., XL, 1892, p. 295. — 



* Fischer and Crosse, Miss. Sci., Pt. 7, II, 1894, p. 518, pi. lxiv, figs. 8-11. 



Lake Chapala, State of Jalisco, Mexico. 



t ANODONTA EXILIOR Lea. 



* Anodonta exilior Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 188; *J1. Ac. N. Sci. 

 Phila., VIII, 1874, p. 24, pi. vii, fig. 21; *0b8., XIII, p. 28,pl. vii, fig. 21.— 

 *B. H. Wright, Check List, 1888.— "Fischer and Crosse, Miss. Sci,, Pt. 7, 

 II, 1894, p. 520. 



"" Anodonta chalcoensis Crosse and Fischer, Jl. de Conch., XLI, 1893, p. 110. — 



* Fischer and Crosse, Miss. Sci., Pt. 7, II, 1894, p. 522, pi. lxiv, figs. 7, la. 



Mexico, mostly in the Pacific drainage. 



(Group of Anodonta dejecta.) 



Shell rather solid, subtrapezoidal, narrower and rounded in front, 

 where it is often considerably thickened,with a slight post-dorsal wing; 

 beaks rather compressed, the sculpture consisting of numerous irregu- 

 lar ridges which have a tendency to become doubly looped and nodu- 

 lous; epidermis rather smooth and sliining, greenish or ashy brown; 

 nacre lurid, darker in the cavity of the beaks j muscle scars irregular, 

 not well defined; dorsal scars few and rather deep. 



Animal with dark colored branchiae, the inner wider in front, nearly 

 or quite free from the abdominal sac, the outer wrinkled on the outside 

 into longitudinal and vertical folds, all four united to the mantle to 

 the extreme posterior end; palpi very large; mantle with a wide, thick- 

 ened double edge; branchial opening with numerous papillae; anal 

 opening smooth ; superanal opening long, deep, united a long way below. 



t ANODONTA DEJECTA Lewis. 



* Anodonta dejecta Lewis, Field and Forest, I (August and September), 1875, p. 

 26;' * Yarrow's Report, 1875, p. 952.— ' B. H. Wright, Check List, 1888.— 

 Simpson, Pr. U. S. Nat. Mus., XIX, 1896, p. 372, pi. xxxii, figs. 4, 5. 



^\ Anodonta mearnsiana Simpson, Nautilus, VI, 1893, p. 134. 



Arizona; southeastern California; northwest Mexico. 



(Group of Anodonta cataracta.) 



Shell thin or solid, inflated, rather evenly rounded in front, generally 

 somewhat biangulate behind, and very slightly winged in the post- 



' Said to be from Arkansas River or its tributaries west of the one hundredth 

 meridian and collected by Dr. H. C. Yarrow, surgeon and naturalist of Wheeler'a 

 expedition. This locality is erroneous, as it belongs, no doubt, exclusively to the 

 Pacific drainage. 



