Bull. U. vS. U. F., 1917-18. 



Plate: XVIII. 



Upper pair: Purply, La^npsilis purpurata (Lamarck), frum Kiamicbi River, Okla. (See p. ^i.) 

 At bottom: Lampsilis muUiradiata{lL,ea), horn. Stone 'Riwer,Tcv.n. (Seep. 31.) 



