598 PROCEEDING S OF THE NA TIONAL M USE UM. VOL. xxn. 



with a straight edge in front; dorsal scars numerous, distinct, placed 

 back of the pseudocardinals; cavity of the beaks not deep or com- 

 pressed ; nacre dull lurid to purplish brown. 



Animal with gills nearly equal in size, inner slightly the larger in front, 

 united the whole length to the abdominal sac; ovisacs apparently 

 separated from each other by a sulcus as in Lampsilis; palpi very large, 

 wide, wrinkled ; mantle having a wide, slightly thickened border, double 

 edged, the inner being beautifully toothed ; branchial opening papillose; 

 anal crenulate; foot small; whole animal the color of the nacre. 



t GLEBULA ROTUND AT A Lamarck. 



* Unio rotundata LAMARCK, An. sans Vert., VI, 1819, p. 75. *LEA, Obs., 1, 1834, p. 



201. 



*Glebula rotundata CONRAD, Pr. Ac. N. Sci. Phila., 1853, p. 268. 



*Unio rotundatus HAXLEY, Test. Moll., 1842, p. 201; *Biv. Shells, 1843, p. 201, pi. 

 xxiii, fig. 30. *CATLOW and REEVE, Conch. Norn., 1845, p. 63. *CONRAD, Pr. 

 Ac. N. Sci. Phila., VI, 1853, p. 257. *H. and A. ADAMS, Gen. Rec. Moll., II, 

 1857, p. 492. *KUSTER, Conch. Cab. Unio,-1861, p. 256, pi. LXXXVI, fig. 4. 

 *REEVE, Conch. Icon., XVI, 1865, pi. xxm, fig. 106. *B. H. WRIGHT, Check 

 List, 1888. *P,ETEL, Conch. Sam., Ill, 1890, p. 166. *CALL, Tr. Ac. Sci. St. 

 Louis, VII, 1895, p. 47, pi. IX. 



* Margarita (Unio) rotundatus LEA, Syn., 1836, p. 33; 1838, p. 23. 



*Margaron ( Unio) rotundatus LEA, Syn. 347, 1852, p. 34; 1870, p. 55. 



*Unio suborbiculata LAMARCK, An. sans Vert., VI, 1819, p. 81. *LEA, Obs., 1, 1834, 

 p. 201. *DESHAYES, An. sans Vert., 2d ed., VI, 1835, p. 546; 3d ed., II, 1839, p. 

 671. 



* Unio suborbiculatus FERUSSAC, Guer. Mag., 1835, p. 26. 



Unio glebulus SAY, Transylvania Jl., IV, 1831, p. 526. SAY, Am. Conch., No. IV, 

 1832, pi. xxxiv ; No. V, 1832, p. 4 (of cover). CONRAD, New F. W. Shells, 

 1834, p. 69. CHENU, Bib. Conch., 1st ser., Ill, 1845, p. 46, pi. xi, figs. 10-12. 

 SOWERBY, Conch. Icon., XVI, pi. LXXIV, fig. 384. 



''Unio glebulus P^ETEL, Conch. Sam., Ill, 1890, p. 154. 



*Unio subglobosus LEA, Tr. Am. Phil. Soc., V, 1834, p. 30, pi. n, fig. 3; *Obs., I, 

 1834, p. 142, pi. n. fig. 3. *SOWERBY, Conch. Icon., XVI, 1868, pi. LXIV, fig. 

 321. 



*Unio granadensis CONRAD,' Pr. Ac. N. Sci. Phila., VII, 1855, p. 256. * B. H. 

 WRIGHT, Check List, 1888. 



Louisiana; eastern Texas; Eio Grande Eiver; Escainbia County. 

 Florida. 



1 Conrad says it is suboval, with the disks somewhat flattened, with minute, radiat- 

 ing lines extending to the tips of the beaks. The rotundata sometimes shows radi- 

 ating ridges at the beaks in eroded specimens. He also states that the nacre of his 

 species is purple. The description therefore fits Lamarck's species perfectly, 

 though I have never known the species to come from so far west as the Rio Grande 

 Conrad's locality. 



