Lampsilis hydiana shell description:

 “Shell of moderate size, normally subsolid but sometimes rather thin, long elliptical, ordinarily much inflated; beaks full and high, their sculpture delicate, consisting of faint, somewhat corrugated double loops, the hinder open behind; surface smooth and shining, sometimes faintly concentrically sculptured, greenish, waxy-yellow, beautifully and boldly rayed with green.  In some cases the rays are broad and very distinct, in others they are split into numerous fine rays with a wider ray of the ground color between them.  Occasional shells are scarcely rayed at all.  Left valve bearing two sharp, sometimes slightly compressed pseudocardinals, and after having a small anterior lamellar third tooth near the edge of the shell; right valve with two pseudocardinals, the lower the larger; laterals curved, one in the right valve and two in the left; anterior muscle scars well marked; posterior scars faint; nacre generally rich silvery, though sometimes bluish and lurid brown in the cavity of the beaks.  The male shell is somewhat pointed behind about midway up from the base; that of the female is rather blunt behind and decidedly swollen at the post-base” (Simpson 1914,Mather 2007).