MONOCONDYI..KA 1 389 



MoNOCONnYL.T;A RRTfcuLATA Aloricaiid. 



Shell subelliptical or subrhomiboid, somewhat inflated, sub- 

 solid, inequilateral ; beaks high and full, turned forward over 

 a sort of lunule ; dorsal outline behind the beaks arched ; pos- 

 terior end obliquely truncate or subtruncate ; anterior end nar- 

 rowed and rounded, angled above ; base curved ; surface hav- 

 ing irregular, concentric strire, which appear as if reticulated ; 

 epidermis cloth-like ; nacre bluish-white ; teeth more or less 

 broken up, subnodulous. 



T.ength 40, height 30, diam. 21 mm. 



Brazil. 

 Monocondylcca reticulata MoriCxAND, Rev. et Mag., X, 1858, 



p. 453, pi. XV, fig. 2.--STMPSON, Syn., 1900, p. 912. 

 Margaron (Monocondylcea) reticulata Lea, Syn., 1870, p. 72. 

 Margarifana reticulata P.5;tet,, Conch. Sam., Ill, 1890, p. 173. 

 Unio reticitlatus Sowerby, Conch. Icon., XVI, 1868, pi. 



i.xxxvi, fig. 458. 

 Aplodon rcticulatus vox Iiihring, Arch, fiir Nat., 1893, p. 115. 



Something like M . paraguayana, but lacking the posterior 

 green rays and the surface is subreticulated, while in that 

 species it is not. 



MoNocoNDYi..ii;A COST [u. ATA Moricand. 



Shell irregularly ovate, inflated, inequilateral, with full, 

 rounded, elevated beaks: dorsal line behind the beaks and 

 dorsal slope curved, a little more prominent behind the liga- 

 ment ; anterior end somewhat narrowed, rounded ; base curved, 

 but emarginate behind the middle at the termination of a shal- 

 low, radial furrow ; posterior ridge rounded, ending near the 

 base of the shell in a blunt, rounded point ; surface with nar- 

 row, radiating ribs ; epidermis dark olive ; nacre bluish-white ; 

 there is a single, thick, primary tooth in each valve. 



Length 34, height 22 mm. 



Brazil.' 

 Monocondylcea costulata Moricand, Rev. et Mag. Zool., X, 



1858, p. 453, pi. XV, fig. I. — Simpson, Syn., 1900, p. 912. 

 Unio costulatus Sowerby, Conch. Icon., XVI. 1868, pi. 



LxxxvTiT, fig. 470. 



