558 HiftC'EKDISr.s or Till-: X ITfOX.IL 



(Group of Lampeilis 



Shell solid, that of the male sinuate at post base, and sometimes pro- 

 duced posteriorly, female shell wider, only slightly sinuous; beak sculp- 

 ture rather coarse, feebly doubly looped; epidermis dark, with wavy, 

 capillary rays; hinge heavy; nacre bluish-white or purple; animal 

 unknown. 1 



t LAMPSILIS TRABALIS Conrad. 



*Unio Irabalis CONRAD, New F. W. Shells, May 3, 1834, p. 27, pi. in, fig. 5; p. 



72. 'FERUSSAt . finer. Mag., 1835, p. 29. *MOLLER, Syn.Nov. Gen., 1836, p. 



201. TOXIJAD, Monog., XII, 1840, p. 110, pi. LX, fig. 2. *( 'HKNI. Kib. Conch., 



1st ser., Ill, 1845, p. 15, pi. n, fig. 3. * CONRAD, Pr. Ac. X.Sci. Phila., VI, 1853, 



p. 259. s B. H. WRIGHT, Check List, 1888. 

 t Unio troostengis LEA, Tr. Am. Phil. Soc., V, 1834 (August or September), p. 71, pi. 



x, fig. 30; * Obs., I, 1834, p. 183, pi. x, fig. 30.* FERUSSAC, Guer. Mag., 1835, 



]( . 29. * HANLEY, Test. Moll., 1842, p. 186; Biv. Shells, 1843, p. 186, pi. xxm, 



fig. 24. CATLOW and REEVE, Conch. Norn., 1845, p. 64. *H. and A. ADAMS. 



Gen. Rec. Moll., II, 1858, p. 496.* KUSTEK Conch. Cab. Uiiio, 1861, p. 193, pi. 



LXI, fig. 4. ' SOWERBY, Couch. Icon., XVI, 1868, pi. LXXVIII, fig. 406. 



*P.KTEL, Conch. Sam., Ill, 1890, p. 170. 



*Margari1a ( Unio) troostensis LEA. Syn., 1836, p. 21 ; 1838. p. 18. 

 *Margaron ( Unio) Iroostensis LKA, Syn.. 1852, p. 25. 

 *Margaron ( Unio) Irooaiii LEA, >Svn., 1870, p. 39. 

 ^ Unio troostil B. II. WRIGHT, Check List, 1888. 

 * Unio raniixemensis SOWKRHY, Couch. Icon., 1866, pi. xxxix, fig. 216. 



Kentucky and streams of Tennessee; Clinch River, Virginia. 



t LAMPSILIS PERPURPUREUS Lea. 



*Unio perpurpurens LEA, Pr. Ac. X. Sci. Phila., V, 1861, p. 41; .11. Ac. N. Sci. 



Phila., VI, 1866, p. 46, pi. xvi, fig. 44 ; * Obs., XI, 1867, p. 50, pi. x vi, fig. 44. 



* B. H. WRIGHT, Check List, 1888. 

 *Margaron ( Unio) perpnrpurens LEA. Syu., 1JS70, p. 48. 

 " I'nio iroostennis SOWERBY, Conch. Icon., XVI, 1868, pi. LXXIX, fig. 415. 



Tennessee lliver, drainage, extending into Virginia in the Clinch. 

 (Group of Jjampsilits modioliformis.) 



Shell elliptical, thin, quite evenly rounded before and behind, some- 

 what inflated; beak sculpture consisting of a fe\v parallel bars, looped 

 in front, and generally open; epidermis with beautiful, rather broad, 

 generally unbroken, sometimes slightly wavy rays; nacre brilliantly 

 iridescent posteriorly; teeth compressed. The female shell is greatly 



1 Certain male shells of L. trabalis differ so remarkably from those of the females 

 and from any other known Xaiades that it might be supposed that they belonged to 

 an isolated group. Other male shells, however, differ but little from the females, 

 and in /,. pcrpurpureus, a species so close to L. trabdJis that it is often difficult to 

 separate them, the male shells differ but slightly from those of the females. 

 Through this former species the group seems very closely related to that of eUipsi- 

 formis, and so on to the assemblage typified by L. iris. 



