SCAMMON : THE UNIONISE OF KANSAS, PART I. 305 



posterior scars faint and fused. Pallial line hardly outlined. 

 Cavity of the shell slight; of the beaks, hardly present. 

 Nacre bluish white, iridescent. 



L. leptodon inhabits the streams of the northern Mississippi 

 drainage and also occurs in Manitoba (Simpson). It has 

 been found in Kansas only in the Neosho river (Call ) . It is 

 the most delicate member of the genus and its outward form 

 may confuse it with the anodons but laterals and pseudo- 

 cardinals are present. 



Genus OBOVARIA Rafinesque, 1819. 



"Shell short, oval, rounded or retuse, solid inflated, thick 

 in front, thinner behind, with high beaks, which are sculp- 

 tured with very faint, irregular, often broken, and slightly 

 nodulous ridge, which shows a tendency to fall into two 

 loops, the posterior often open behind ; epidermis dull, 

 brownish, silky or cloth-like, rarely rayed, rays indistinct; 

 female shell but slightly inflated in the post-basal region, 

 commonly having a shallow furrow or flattened area at the 

 posterior end ; pseudocardinals solid, stumpy ; laterals short, 

 club-shaped ; anterior and posterior cicatrices deep and dis- 

 tinct ; nacre bluish white or purple. 



"Animal with very short gills, the inner united to the ab- 

 dominal sac throughout, marsupium projecting far below the 

 rest of the branchire and occupying the posterior portion of 

 the outer gills, dolabriform or kidney-shaped ; mantle with 

 a wide, thickened, double-edged border, the inner edge 

 of which is often slightly toothed at its post-basal part." 

 ( Simpson.) 



Obovaria ellipsis Lea. Plate LXIX, fig. 2. 



Unvo ellipsis Lea, Trans. Amer. Phil. Soc, in, 1828, p. 268, pi. iv, 



fig. 4. 

 Unio pearlii Lea, Proc. Acad. Nat. Sci. Phila., I, 1874, p. 191. 



Shell of moderate size, short, oval, quite heavy, particularly 

 anteriorly, somewhat inflated. Anterior margin rounded ; 

 ventral margin decidedly bowed ; posterior margin rounded 

 or roundly pointed dorsally ; dorsal margin rather curved, 

 and meeting the posterior at a quite variable angle of from 

 130 to 160 degrees. Umboidal ratio generally small but very 



