MONOCONPYL.^A 1 39 I 



colored spots; hinge thick, having two teeth, one of which is 

 smaller than the other ; nacre white, pearly. 



Length 20, height 15, diam. 3 mm. 



Amazon. 

 Unio jaspidea Hupe, An. Nouv.. Ill, 1857, p. 83. pi. xvii. 



fig. 2. 

 Margaron (Unio?) jasHdcits I.ka, Syn., 1870, p. 37. 

 Monocondylcca jaspidca Simpson, Syn., 191 1, p. 912. 



Hupe calls this a Ufiio, but from his description and figure 

 I think it is a Monocondylcra. The remarkably rough, rasp- 

 like surface, colored green, with small, angular jasper-colored 

 spots distinguish it from all other species. Hupe gives the 

 diameter as 3 millimeters, which may be an error as this would 

 make a most remarkably compressed shell. It may be that it 

 should have been 8 millimeters. 



Group of Monocondylcea franciscana. 



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

 sometimes slightly produced at the post-basal region ; beaks 

 rather low. 



MoNOCONDYL.ivA FRANCISCANA Aloricand. 



Shell suborbicular, subinflated, subsolid, nearly equilateral ; 

 beaks full, somewhat elevated; dorsal outline very lightly 

 arched ; dorsal slope almost squarely subtruncate ; the remain- 

 der of the shell nearly evenly rounded, a little fuller behind 

 the middle of the base ; surface nearly smooth with a cloth-like, 

 greenish epidermis, with two or three faint, dark rays on the 

 posterior part ; nacre bluish, somewhat iridescent ; tooth of the 

 left valve in front of the beak, that of the right opposite the 

 beak ; both are compressed and rounded. 



Length 38, height 34, diam. 1 1 mm. 



Brazil. 

 Unio (Monocondylaa) franciscana Mokicand, Mem. Nat. 



Soc. Hist. Nat; Gen., VHL 1837, p. 39, pi. in, figs. 14-17. 

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

 Margaron (MonocondyUca) franciscana Lea, Syn., 1852, p. 



45 ; 1870, p. 72. 



