﻿8o lAMi'snjs 



lateral ; beak cavities not deep ; muscle scars large, well im- 

 pressed and smooth ; nacre white or pink, much thickened in 

 front in old shells ; female shells very slightly produced at pos- 

 terior base. 



Length 140, height 90, diam. 58 mm. 



Mississippi River drainage generally ; southern Michigan ; 

 western New York ; Manitoba ; Ontario. 



Type locality, Ohio River. 

 Unio crassus Say, Nich. Encyc, II, 1817, pi. 1, fig. 8. — Hii,e>- 



RETH, Am. Jl. Sci., XIV, 1828, p. 278, fig. i. — Sowerby, 



Conch. Icon., XVI, 1866, pi. xiv, fig. 220. 

 Margarita (Unio) crassus Lea, Syn., 1836, pi. 24; 1838, p. 19. 

 Mya crassa Eaton, Zool. Text-Book, 1826, p. 217. 

 Unio ligamentina Lamarck, An. sans Vert., VI, 1819, p. 72. 

 Unio ligamentinus Kuster, Conch. Cab. Unio, 1852, p. 23, pi. 



Ill, fig. 3. — Call, Tr. x\c. Sci. St. Louis, VII, p. 22, pi. 



XXI. 



Margaron (Unio) ligamentinus Lea, Syn., 1852, p. 28 ; 1870, 



P-43- 

 Lampsilis ligamentinus Baker, Moll. Chicago, Pt. I, 1898, p. 



108, pi. XVI, — Smith, Bull. U. S. F. Com., 1899, p. 291, pi. 



Lxxix. — Simpson, Syn., 1900, p. 539. 

 Ncphronajas ligamentina Ortmann, Ann. Car. Mus., VIII, 



19 1 2, p. 325. 

 Unio ellipticus Barnes, Am. Jl. Sci., VI, 1823, p. 259, pi. 



XIII, fig. 19 (outline). 

 Mya elliptica Eaton, Zool. Text-?jook, 1826, p. 219. 

 Unio carinatus Baenes, Am. Jl. Sci., VI, 1823, p. 259, pi. xr. 



fig. 10. 

 Mya carinata Eaton, Zool. Text-Book, 1826, p. 220. 

 Unio ellipsarius Say, Am. Conch. VI, 1834. 

 Unio fasciatus Say, Am. Conch., VI, 1834. — Conrad, Monog., 



1835, p. 3, pi. I. — PoTiEz and Michaud, Gall. Moll., 18/^4, p. 



153, pi. Lviii, fig. 5. — Kuster, Conch. Cab., 1852, p. 31, pi. v, 



fig- 3- 

 Mya gravis Wood, Ind. Test., (Hanley) 1856, p. 199, pi. i, 



fig. 6. 



