668 PROCEEDINGS OF THE NATIONAL MUSEUM. 



ridges in front and behind; pseudocardinals rather solid; laterals very 

 faint; marsupium occupying the whole of the outer gills, thick, pad- 

 like; inner gills wholly or partly free from the abdominal sac; mantle 

 bordered with square, black spots. 



fALASMIDONTA CALCEOLA Lea. 



■ Unto calceolus Lea, Tr. Am. Phil. Soc. , III, 1830, p. 265, pi. iii, fig. 1 ; * Obs., 1, 1834, 

 p. 7, pi. Ill, fig. 1.—" FERUSSA.C, Gner. Mag., 1835, p. 26.—* Chenu, 111. Conch., 

 1858, pi. VIII, figs. 2, 2a, 2c.—* Kuster, Conch. Cab. Unio, 1861, p. 187, pi. lix, 

 fig. 3. 



*Siro2)hitHS calceolus Coxrad, Pr. Ac. N. Sci., Phila., VI, 1853, p. 262. 



* Unio calceola Deshaye^, An. sans Vert., 2d ed., VI, 1835, p. 546; 3d ed., II, 1839, 



p.672.— *HANLEi',Test.Moll., 1842, p. 212; *Biv. Shells, 1843, p. 212, pi. xxii, 



fig. 29. — * Catlow and Eeeve, Couch. Nom., 1845, p. 56. — * Sowerby, Conch. 



Icon., XVI, 1868, pi. Lxxviii, fig. 410. 

 *Margorita (Margaritana) calceola Lea, Syn., 1836, p. 45; 1838, p. 27. 

 ^Margaron {Margaritana) calceola Li5a, Syn., 1852, p. 43; 1870, p. 68. 

 *Margaritana calceola Kuster, Conch. Cab. Unio, 1862, p. 299, pi. xcix, fig. 6. — 



*"b. H. Wright, Check List, 1888.— * PiETEL, Conch. Sam., Ill, 1890, p. 172. 

 ""Bapliia calceola H. and A. Adams, Gen, Kec. Moll., II, 1857, p. 500. 

 * Alasmodonta truncaia Conrad, New F. W. Shells, 1834, p. 73. 



* Margarita {Margaritana) deltoidea Lea, Syn., 1836, p. 44; 1838, p, 27. 

 "Margaritana deltoidea Lea, Tr, Am. Phil, Soc, VI, 1838, p, 43, pi. xiii; fig. 38; 



Obs., II, 1838, p. 43, pi. xiii, fig. 38.— * Trosciiel, Arch, fiir Nat,,V, 1839, II, 



p. 238.— * Chenu, Man., 1859, II, p. 144, fig. 711.—^ Kuster, Conch. Cab., 1862, 



p. 299, pi. xcix, fig. 5.—* Calkins, Pr. Ottawa Ac. Sci., 1874, p, 46,— *B, H. 



Wright, Check List, 1888.— * P^etel, Conch, Sam., Ill, 1890, p. 173. 

 *Unio deltoidea Hanley, Test, Moll., 1842, p. 211; *Bi\^ Shells, 1843, p, 211, pi, 



XXII, fig. 50, 

 *Margaron {Margaritana) deltoidea Lea, Syn., 1852, p. 42, 1870, p. 67. 

 ""Strojjhitus deltoidea Conrad, Pr. Ac, N, Sci,, Phila., VI, 1853, p. 263. 

 ""Baphia deltoidea H. and A. Adams, Gen. Eec, Moll,, II, 1857, p. 499. 

 "Alasmodonta deltoidea Baker, Moll. Chicago, Pt. 1, 1898, p. 63, pi. vi, fig. ?,- 



VII, fig. 4. 

 "" Unio deltoideus Catlow and Eeeve, Conch. Nom., 1845, p, 58, — * Sowerby, 



Conch, Icon., XVI, 1868, pi. Lxxvi, fig. 395. 



Upper Mississippi drainage; Ohio, Cumberland, and Tennessee rivers; 

 Lower and Middle St. Lawrence systems. 



fALASMIDONTA MINOR Lea. 



* Margaritana minor Lea, Pr. Am. Phil. Soc, IV, 1845, p, 166; Tr. Am. Phil. Soc, 



X, 1848, p. 82, pi. VIII, fig. 26; *Obs,, IV, 1848, p. 56, pi, viii, fig. 26,—* Chenu, 

 Man., 1859, II, p. 144, fig. 713.— *B. H, Wright, Check List, 1888.—* Pjstel, 

 Conch. Sam., Ill, 1890, p, 173, 



""Strophitus minor Conrad, Pr. Ac. N. Sci., Phila., VI, 1853, p. 263. 



'^Margaron {Margaritana) minor Lea, Syn., 1852, p. 42; 1870, p. 67. 



*Baphia minor H. and A. Adams, Gen, l^ec. Moll,, II, 1857, p. 499. 



Tennessee and Cumberland river systems. 



(Group of Alasmidonta heterodon.) 



Shell small, rather thin, rhomboid; beak sculpture very strong, con- 

 sisting of concentric ridges or irregular corrugations, often slightly 



