﻿LAMPSILIS 123 



one lateral ; muscle scars shallow ; nacre dirty and livid. The 

 male and female shells seem to differ but little, the latter appar- 

 ently have a faint marsupial swelling'. 



Length 60, height 35, diam. 17 mm. • 



Type locality, Big Pigeon River, Tenn. Also, French Broad 

 River, Tenn. ; near Bowling Green, Kentucky. 

 Unio tener Lea, Pr. Am. Phil. Soc, T, 1840, p. 286; Tr. Am. 



Phil. Soc, Vin, 1840, p. 198, pi. X, fig. 10; Obs., Ill, 1842, 



p. 36, pi. X, fig. 10. — Chenu, 111. Conch., 1858, pi. xxxi, figs. 



I, la, lb. 

 Margaron (Unio) tener Lea, Syn., 1852, p. 28; 1870, p. 44. 

 Lampsilis tener Simpson, Syn., 1900, p. 555. 

 Unio regularis Lea, Pr. Am. Phil. Soc, II, 1841, p. 82; Tr. 



Am, Phil. Soc, VIII, 1842, p. 243, pi. xxv, fig. 59; Obs., Ill, 



1842, p. 81, pi. xxv, fig-. 59.— Chenu, 111. Conch., 1858, pi. 



xxxiii, fig-s. 3, 3a, 3&. — SowERBY, Conch. Icon., XVL 1868, 



pi. LXVIII, fig. 351. 



Margaron (Unio) regularis Lea, Syn., 1852, p. 29 ; 1870, p. 45. 

 Lea's Unio tener is represented in his collection by only a 

 single broken shell, which I have no hesitation in saying is iden- 

 tical with his U. regularis, of which he has two very badly 

 eroded specimens. 



Lampsius sima (Lea). 



Shell oval or elliptical, not inflated, solid, with low, compress- 

 ed, beaks, which are sculptured with irregular, somewhat 

 doubly-looped ridges ; posterior ridge low and rounded ; surface 

 rudely and irregularly concentrically striate in old specimens, 

 smoother in young shells, yellowish-green, greenish-yellow or 

 tawny, with numerous wavy rays, often shining in well-preserv- 

 ed shells ; left valve with two stumpy pseudocardinals and two 

 short laterals ; right valve with one pseudocardinal and a feeble 

 one above it, with one lateral ; beak cavities shallow, showing 

 a few dorsal pits ; muscle scars well marked ; pallial line well 

 impressed in front ; nacre pinkish or purple, sometimes bluish- 

 white, with a darker center, thickened in front, iridescent be- 

 hind. The male shell is somewhat oval, sometimes being 



