912 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxu. 



tMONOCONDYL^A RETICULATA Moricand. 



■* MonoconclyUva reUcidaia Moricand, Eev. et Mag., X, 1858, p. 453, pi. xv, fig. 2. 



^ Margaron {Monoconchjlwa) reticulata Lea, Syn., 1870^ p. 72. 



'^ Margaritana reticulata Tjetel, Conch. Sam., Ill, 1890, p. 173. 



^ Uodo reticulatus SowERBY, Conch. Icon., XVI, 1868, pi. lxxxvii, fig. 458. 



'" Jplodon reticulatus VON IiiERiNG, Arch, fiir Nat., 1893, p. 115. 



Brazil. 



MONOCONDYL.^A COSTULATA Moricand. 



* Monocondylaa costulata Moricand, Eev. et Mag. Zool., X, 1858, p. 453, pi. xv, fig. 1; 



* SowERBY, Conch. Icon., XVI, 1868, pi. Lxxxviii, fig. 470. — * P/etel, Conch. 

 Sam., Ill, 1890, p. 174. 



" Margaron (Monocondylcea) costulata Lka, Syn., 1870, p. 72. 



Brazil. 



t MONOCONDYLiEA CORRIENTESENSIS d'Orbigny. 



* Monocondylcea corrieniesensis 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.— 



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

 ^Margarita {Monocondylaa) corrientesensis Lea, Syn., 1838, p. 28. 

 ""Unio corrientesensis Hanley, Test. Moll., 1842, p. 212; "Biv. Shells, 1843, p. 212, 



pi. XXII, fig. 15. — *Catlow and Reeve, Conch. Nom., 1845, p. 57. — *Sowerby, 



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

 *Margaron {Monocondylam) corrientesensis Lea, Syn., 1852, p. 45; 1870, p. 73. 



Argentina. 



MONOCONDYL^A JASPIDEA Hupe. 



* Unio jaspidea Hupe, An. Nouv., Ill, 1857, p. 83, pi. xvii, fig. 2.' 

 ^Margaron ( Unio'i) jasjrideus Lea, Syn., 1870, p. 37. 



Amazon. 



(Group of Monocondylcea franciscana.) 



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

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



t MONOCONDYLiEA FRANCISCANA Moricand. 



* Unio (Monocondylwa) franciscana Moricand, Mem. Soc. Hist. Nat. Gen., VIII, 



1837, p. 39, pi. Ill, figs. 14-17.— * Troschel, Arch, fiir Nat., VIII, 1842, Pt. 2, 

 p. 404. 



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



* Mar gar on (Monocondylcea) franciscana Lea, Syn., 1852, p. 45; 1870, p. 72. 



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



* Clessin, Conch. Cab. Ano., 1876, p. 251, pi. lxxiv, figs. 4, 5. — *PiETEL, 

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



* Aplodon franciscana von Ihering, Arch, fiir Nat., 1893, jt. 115. 



Brazil. 



tMONOCONDYL.^A LENTIFORMIS Lea. 



* Monocondylcea lentiformis Lea, Pr. Ac. N. Sci. Phila., X, 1866, p. 34; * Jl. Ac. N. 



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

 fig. 86.— *Clessin, Conch. Cab. Ano., 1876, p. 250, pi. Lxxix, figs. 4, 5.— 

 *P^tel, Conch. Sam., 1890, p. 174. 



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



