912 PROCEEDINGS OF THE NATIONAL MUSEUM. VUL.XXII. 



tMONOCONDYL^EA RETICULATA Moricand. 



* Monocotidyla'a reticulata MORICAND, Eev. et Mag., X, 1858, p. 453, pi. xv, fig. 2. 



* Margaron (Monocondyltra) reticulata LEA, Syn., 1870, p. 72. 



* Margaritana reticulata P.KTEL, Conch. Sam., Ill, 1890, p. 173. 



* Unio reticulatus SOWERBY, Conch. Icon., XVI, 1868, pi. i.xxxvn, fig. 458. 



* Aplodon reticulatus VON IHERING, Arch, fiir Nat., 1893, p. 115. 



Brazil. 



MONOCONDYL^A COSTULATA Moricand. 



* Monocondyla-a costulata MORICAND, Rev. ct Mag. Zool., X, 1858, p. 453, pi. xv, fig. 1; 



* SOWERBY, Conch. Icon., XVI, 1868, pi. LXXXVIII, fig. 470. * P.ETKL, Conch. 

 Sam., Ill, 1890, p. 174. 



*Margaron (Monocondylcea) costulata LEA, Syn., 1870, p. 72. 



Brazil. 



t MONOCONDYL^A CORRIENTESENSIS d'Orbigny. 



* Monocondyl(ta corrientesensis D'ORBIGNY, Gner. Mag., 1835, p. 38 ; * Voy. Am. Mer., 

 1843, p. 615, pi. LXVII, figs. 8-10. *H. and A. ADAMS, Gen. Rec. Moll., II, 1857, 

 p. 501. * CLESSIN, Conch. Cab. Ano., 1876, p. 246, pi. LXXVIII, figs. 3, 4. 

 *PTEL, Conch. Sam., Ill, 1890, p. 174. 



* Margarita (Monocondylosa) corrientesensis LEA, Syu., 1838, p. 28. 



*Unio corrientesensis HANLEY, Test. Moll., 1842, p. 212; * Biv. Shells, 1843, p. 212, 

 pi. xxn, fig. 15. * CATLOwandRuKVE, Conch. Noin., 1845, p. 57. * SOWERBY, 

 Conch. Icon., XVI, 1868, pi. xcm, fig. 509. 



*Margaron (Monocondyla'a) corrientesensis LEA, Syu., 1852, p. 45; 1870, p. 73. 



Argentina. 



MONOCONDYLAA JASPIDEA Hupe. 



* Uniojaspidea HUPE, An. Nouv., Ill, 1857, p. 83, pi. xvn, fig. 2.' 

 *Mar<jaron ( Uniol) jaspideus LEA, Syn., 1870, p. 37. 



Amazon. 



(Group of Monocondylcea franciscana.} 



Shell moderately inflated, lenticular, rounded, not very solid; some- 

 times slightly produced at the post basal region ; beaks rather low. 



t MONOCONDYLCEA FRANCISCANA Moricand. 



* Unio (Monocondyla-a) franciscana MORICAND, Mem. Soc. Hist. Nat. Gen., VIII, 



1837, p. 39, pi. in, figs. 14-17.* TROSCHEL, Arch, fiir Nat., VIII, 1842, Pt. 2, 

 p. 404. 



* Margarita (Margaritana) franciscana LEA, Syn., 1838, p. 35. 



* Mar gar on (Monocondylaa) franciscana LEA, Syu., 1852, p. 45; 1870, p. 72. 



* Monocondylcea franciscana H. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 501. 



* CLESSIN, Conch. Cab. AUG., 1876, p. 251, pi. LXXIV, figs. 4, 5. "P.ETEL, 

 Conch. Sam., Ill, 1890, p. 174. 



* Aplodon franciscana VON IHERING, Arch, fiir Nat., 1893, p. 115. 



Brazil. 



t MONOCONDYLAA LENTIFORMIS Lea. 



* Monocondylcea lentiformis LEA, Pr. Ac. N. Sci. Phila., X, 1866, p. 34; *J1. Ac. N. 



Sci. Phila., VI, 1868, p. 272, pi. xxxvi, fig. 86 ; *Obs., XII, 1869, p. 32, pi. xxxvi, 

 fig. 86. *CLESSIN, Conch. Cab. Ano., 1876, p. 250, pi. LXXIX, figs. 4, 5. 

 *P.ETEL, Conch. Sam., 1890, p. 174. 



1 The figure shows the teeth, which appear to be those of a Monocondylcea. 



