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. 



* Unio calceolus LEA, Tr. Am. Phil. Soc., Ill, 1830, p. 265, pi. in, fig. 1 ; * Obs., 1, 1834, 



p. 7, pi. in, fig. 1.* FERUSSAC, Gner. Mag., 1835, p. 26.* CHENU, 111. Conch., 

 1858, pi. vin, tigs. 2, 2a, 2c. * KUSTER, Conch. Cab. Unio, 1861, p. 187, pi. LIX, 

 fig. 3. 

 *Strophitns calccolus COXRAD, Pr. Ac. N. Sci., Phila., VI, 1853, p. 262. 



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



p. 672. *HANLEY, Test. Moll., 1842, p. 212; *Biv. Shells, 1843, p. 212. pi. xxu, 



fig. 29.* CATLOW and REEVE, Conch. Norn., 1845, p. 56.* SOAVERBY, Conch. 



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



"Margarita (Margaritana) calceola LEA, Syn., 1836, p. 45; 1838, p. 27. 

 *Margaron (Margarltana) calceola LKA, Syn., 1852, p. 43; 1870, p. 68. 

 "Margaritana calceola KUSTER, Conch. Cab. Unio, 1362, p. 299, pi. xcix, fig. 6. 



* B. H. WRIGHT, Check List, 1885. * PJETEL, Conch. Sam., Ill, 1890, p. 172. 

 *Bapliia calceola H. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 500. 

 *Alasmodonta Iruncata 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. xin; fig. 38; 



Obs., II, 1838, p. 43, pi. xni, fig. 38.* TROSCHEL, Arch, fur 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; * Bh'. Shells, 1843, p. 211, pi. 

 xxu, fig. 50. 



*Mar(jaron (Margaritana) deltoidea LEA, Syn., 1852, p. 42, 1870, p. 67. 



*Strophitu8 deltoidea CONRAD, Pr. Ac. N. Sci., Phila., VI, 1853, p. 263. 



*Baphia deltoidea H. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 499. 



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

 vn, fig. 4. 



* Unio deltoideus CATLOW and REEVE, Conch. Norn., 1845, p. 58. * SOWERBY, 



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



UpperMississippi drainage; Ohio, Cumberland, and Tennessee rivers; 

 Lower and Middle St. Lawrence systems. 



fALASMlDONTA MINOR Lea. 



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



X, 1848, p. 82, pi. vin, fig. 26; * Obs., IV, 1848, p. 56, pi. vin, fig. 26.* CHENU, 

 Man.. 1859, II, p. 144, fig. 713. *B. H. WRIGHT, Check List, 1888.* P.ETEL, 

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



*Strophitii8 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. hec. 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 



