568 PROCEEDINGS OF THE NATIONAL MCSEUM. 



tLAMPSILIS ALATUS var. POULSONI Conrad. 



* Unio poulsoni CONRAD, New F. W. Shells, 1834, p. 25, pi. i, p. 71. * MILLER, 



Syn. Nov. Gen., 1836, p. 200. *CHENU, Bib. Conch., 1st ser., Ill, 1845, p. 15, 

 pi. i, fig. 7. *B. H. WRIGHT, Check List, 1888. * P/ETEL, Conch. Sam., Ill, 

 1890, p. 164. 



* Symphynota poulsoni FERUSSAC, Guer. Mag., 1835, p. 25. 



* Unio inflatns CONRAD, Monog., VII, 1836, p. 57, pi. xxxu. 1 



Entire Mississippi drainage as far south as Arkansas; St. Lawrence 

 drainage; Bed River of the North; the variety in the Alabama and 

 Tombigbee systems. 



tLAMPSILIS COLORADOENSIS Lea. 



* Unio coloradoensis LEA, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 103; Ml. Ac. N. Sci. 



Phila., Ill, 1858, p. 314, pi. xxxi, fig. 29; Obs., VI, 1857, p. 34, pi. xxxi, fig. 

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

 *Margaron ( Unio) coloradoensis LEA, Syn., 1870, p. 41. 



Eastern Texas. 



tLAMPSILIS ROVIROSAI Pilsbry. 



* Unio (Lampsilis) rovirosai PILSBRY, Nautilus, XIII, 1900, p. 140. 

 Laguna de Atasta, near San Juan Bautista, Mexico. 



tLAMPSILIS PURPURATUS Lamarck. 



* Unio purpurata LAMARCK, An. sans Vert., VI, 1819, p. 71. * STARK, Nat. Hist., 



II, 1828, p. 90.* DESHAYES, An. sans Vert.. 2d ed., VI, 1835, p. 533 ; 3d ed., II, 

 1839, p. 667. 



* UniopurpnratusLKA, Obs., 1, 1834, p. 199.* FERUSSAC, Guer. Mag., 1835,|p. 26. 



* HANLEY, Test. Moll., 1842, p. 208; * Biv. Shells, 1843, p. 208, pi. XXII, fig. 5. 



* CATLOW and REEVE, Conch. Nom., 1845, p. 63. * CONRAD, Pr. Ac. N. Sci. 

 Phila., VI, 1853, p. 255.* KUSTER, Conch. Cab. Unio, 1861, p. 185, pi. LIX, 

 fig. 1. * REEVE, Conch. Icon., XVI', 1865, pi. xxiv, fig. 115. * B. H. WRIGHT, 

 Check List, 1888. * PASTEL, Conch. Sara., Ill, 1890, p. 164. * PILSBRY, Nau- 

 tilus, V, 1891, p. 76.* CALL, Tr. Ac. Sci. St. Louis, VII, No. 1, 1895, p. 38, pi. v. 



* Margarita ( Unio) purpuratiis LEA, 1836, p. 39 ; 1838, p. 25. 



* Margaron ( Unio) purpuratiis LEA, Syn., 1852, p. 38; 1870, p. 61. 



t Unio ater LEA, Tr. Am. Phil. Soc., Ill, 1830, p. 426, pi. vn, fig. 9; *Obs., 1, 1834, 

 p. 40, pi. vii, fig. 9. *COXRAD, New F. W. Shells, 1834, p. 67.* CHENU, 111. 

 Conch., 1858, pi. x, figs, la, 16. 



Unio atra DESHAYES, Euc. Meth., II, 1830, p. 582. 



* Unio lugubris SAY, Am. Conch., V, 1832, pi. XLIII ; VI, 1834. 



* Unio poulsoni SOWERBY. Conch. Icon., XVI, 1866. pi. LI, fig. 270. 



* Unio dolo8H8 LEA,* Pr. Ac. N. Sci. Phila., IV, 1860, p. 307; * Jl. Ac. N. Sci. Phila., 



V, 1862, p. 75, pi. ix, fig. 224; * Obs., VIII, 1862, p. 79, pi. ix, fig. 224. 'Sow- 



1 The variety poulsoni is narrower anteriorly and more drawn at the post-basal 

 point than the type, and this form is common in the streams that drain into the Gulf 

 east of the Mississippi, but it seems to connect with typical alatiis in Tennessee. 



-A miserable, worn, young specimen of what I am quite sure is L. purpnratus. Lea 

 states that the embryos of this are pouch-shaped, while those of purpuratus are wedge- 

 shaped, but the form of embryos in a given species is often not constant. 



