670 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxii. 



(Group of Alasmidonta holstonia,) 



Shell subsolid, beak sculpture rather strong, decidedly doubly 

 looped, surface brownish, slightly rayed; pseudocardinals delicate; 

 laterals nearly or quite wanting. Animal like that of A. calceola. 



t ALASMIDONTA HOLSTONIA Lea. 



* Margaritana holstonia Lea, Tr. Am. Phil. Soc, VI, 1838, p. 42, pi. xiii, fig. 37; 



*Obs., II, 1838, p. 42, pi. xiii, fig. 37.—* Tkoschel, Arcli. fiir Nat.,V, 1839, Pt. 2, 

 p.238.— * B.H.Wright, Check List, 1888.— *P/ETEL, Couch. Sam., Ill, 1890, 

 p. 173. 



* Margarita (Margaritana) holstonia Lea, Syn. , 1836, p. 46; 1838, p. 28. 

 "^ Margaron (Margaritana) holstonia Lea, Syn., 1852, p. 44; 1870, p. 70. 



* Strophitns holstonia Conrad, Pr. Ac. N. Sci. Phila., VI, 18.53, p. 263. 



* BapUa holstonia H. and A. Adams, Gen. Rec. Moll., II, 1857, p. 499. 



* Unio h olstonian Its HATSii^iiY, Biv. Shells, 1843, p. 213, pi. xxii, fig. 44.— *Catlow 



and Reeve, Couch. Nom., 1845, p. 60.— ^Sowerby, Couch. Icon., XVI, 1868, pi. 



Lxxvi, fig. 398. 

 ^Margaritana holstoniana Kuster, Couch. Cab. Unio, 1862, p. 302, pi. c, fig. 4. 

 ^ f Unio striatus Sowerby, Couch. Icon., XVI, 1868, pi. Lxxviii, fig. 407. 



Tennessee River system; headwaters of the Coosa River. 



t ALASMIDONTA GEORGIANA Lea.i 



^Margaritana etowahensis ljiiA,VT. Ac. Nat. Sci. Phila., II, 1858, p. 138; *J1. Ac. 



Nat. Sci. Phila., IV, 1859, p. 227, pi. xxxi, fig. 110; *Obs., VII, 1859, p. 4.5, pi. 



XXXI, fig. 110.—* B. H. Wright, Check List, 1888. 

 "^ Margaritana (Alasmodonta) etowahe^isia Clvissiis!, Conch. Cab. Ano., 1875, p. 270. 



pi. LXXXI, figs. 1, 2. 

 ^Margaritana eiowahensis Pjetel, Conch. Sam., Ill, 1890, p. 173. 

 ^Margaritana georgiana Lea, Pr. Ac. Nat. Sci, Phila., Ill, 1859, p. 280. — B. H. 



Wright, Check List, 1888. 

 ^ Margaron (Margaritana) georgiana Lea, Syn., 1870, p. 68. 

 " Alasmodonia inipressa Anthony, Am. Jl. Conch., 1, 1865, p. 157, pi. xii, fig. 4. 



Tennessee; Etowah River, Georgia. 



Subgenus RUGIFERA Simpson, 1900, 

 (Type, Alasmodonta marginata Say.) 



Shell elongated, rhomboid, inflated, surface brilliantly painted with 

 radiations, which often break into a dappled or splashed pattern of 

 color; posterior slope slightly corrugated; teeth very imperfect; lat- 

 erals wanting. 



Animal with a thick, smooth, pad like marsupium. Mantle with 

 square spots behind. 



t ALASMIDONTA MARGINATA Say 



* Alasmodonta marginata Say, Nich. Enc, 1819, No. 1; Am. Conch., VI, 1834. — 



*^ Conrad, New F. W. Shells, 1834, p. 72.—' Ferussac, Guer. Mag., 1835, p. 

 25. — * Stimpson, Shells of N. Eng., 1851, p. 15. — * Agassiz, Arch. fiir. Nat., I, 

 1852, p. 46.—* Conrad, Pr. Ac. Nat. Sci. Phila., VI, 1853, p. 262. 



1 First called Margaritana etowahensia by Dr. Lea, but as that name had previously 

 been used by Conrad its author changed it to georgiana. 



