﻿SYMI'I-IYNOTA 485 



shining, often dull ; left valve with one or more blurred teeth 

 at and in front of the beak, the hinder in perfect examples is 

 compressed and retlexed, with one or more delicate, imperfect 

 laterals ; right valve with one compressed pseudocardinal, 

 which often has irregular denticles behind it, and one lateral ; 

 nacre bluish-white, often buff or straw-tinted. 



Length 60, height 33. diam. 19 mm. 



Streams draining into the Atlantic from New York south 

 to North Carolina. 



Type locality. Juniata River, Pa. 

 Unio I'iridis Conrad, Monog., IV, 1836, p. 35, pi. xvii_, fig. i. 



— Sowa\RBY, Conch. Icon., XYI, 1866, pi. xlv, fig. 244. 

 Symphynota liridis Simpson, Syn., 1900, p. 663. 

 Margarita (Unio) tappanianus Lea, Syn., 1836, p. 39; 1838, 



P- 25. 

 Unio tappanianus Lea, Tr. Am. Phil. Soc, VI, 1838, p. 62, 



pi. XVII, fig. 55 ; Obs., II, 1838, p. 62, pi. XVII, fig. 55. — Han- 

 ley, Biv. Shells, 1843, P- 209, pi. xxi, fig. 38. — De Kay, Zool. 



of N. Y., Pt. 5. 1843, P- 194' pl- XX, fig. 242. — Chenu, 111. 



Conch., 1858, pi. XX, figs. 2, 20, 2h. — Kuster, Conch. Cab. 



Unio, 1862, p. 270, pi. xci, fig. 3. — Uartman and Mich- 



ENER, Conch. Cest., 1874, p. 89. fig. 185. 

 Margaron (Unio) tappanianus Lea, Syn., 1852, p. 39; 1870, 



p. 62. 

 Unio tappianus Catlow and Reeve, Conch., Norn., 1845, p. 64. 

 Unio hyalimis Lea, Pr. Am. Phil. Soc, IV, 1845, P- 164; Tr. 



Am. Phil. Soc, X, 1848, p. 69, pi. 11, fig. 4; Obs., IV, 1848, 



p. 43, pi. II, fig. 4. — Kuster, Conch. Cab. Unio, 1861, p. 204, 



pi. LXVIII, fig. 3. 

 Margaron (Unio) hyalinus LE/\, Syn., 1852, p. 39; 1870, p. 62. 

 Unio pcrtcnuis Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p. 193 ; 



Jl. Ac N. Sci. Phila., VI, 1866, p. 8, pi. 11, fig. 4; Obs., XI, 



1867, P- 12, pi. II, fig. 4. 

 Margaron (Unio) pcrtennis Lea, Syn., 1870, p. 62. 



Smaller and less distinctly rhomboid than 5. pressus. The 

 pseudocardinals are not so perfect as they are in that species. 



