[1ST I 



New Unionida- of the United States and Arctic America. 



By Isaac Lea. 



Since my last publication in the Academy's Journal, I have received a number 

 of new species of Unionidai, of which I published simple diagnoses in the Proceed- 

 ings. I now offer them with full descriptions and observations, and with well 

 characterized figures. They are generally of great interest, coming usually from 

 distant waters, which are not easily attainable. To the Smithsonian Institution I 

 am greatly indebted for the examination of all their species. Those from Arctic 

 America are the first we have seen from the great lakes of that region. 



Unio Wardii. PI. 24, fig. 257. 



Testa tubereulata, subtriangulari, compresstt, subequilaterali, postice et inferne emarginata, antice 

 rotunda ; valvulis crassiusculis, autice 1 erassioribus ; natibus prominulis, ad apices rugosis ; epi- 

 dermide vel luteola vel luteo-virente, niaculis triangularis indutis ; dentibus cardinalibus sub- 

 grandibus, compressis sulcatisque; lateralibus sublongis, subcrassis, obliquis rectisque; margaritS 

 argentea, interdum rosea et iridescente. 



Shell tuberculate, subtriangular, compressed, nearly equilateral, emarginate 

 behind and below, round before; valves somewhat thick, thicker before; beaks 

 slightly prominent and rugose at the tips; epidermis yellowish or yellow green, 

 covered with triangular spots ; cardinal teeth somewhat large, compressed and 

 sulcate ; lateral teeth rather long, rather thick, oblique and straight ; nacre silver 

 white, sometimes rosaceous and iridescent. 

 Proc. Acad. Nat. Sci., 1861, p. 392. 

 Hah. — Walhonding River, Ohio, J. C. Ward. Wassepinicon River, Iowa, Dr. 

 Foreman. Coal River, Logan co., Va., Dr. Hartman. 



My cabinent and cabinets of Dr. Foreman, Dr. Hartman and Mr. Anthony. 

 Diam. 1-2, Length 1-9, Breadth 2-G inches. 



Shell tuberculate, subtriangular, verging to quadrate, compressed, nearly equi- 

 lateral, emarginate behind and below, round before ; substance of the shell somewhat 

 thick, thicker before ; beaks rather prominent, rugose at the tips, ligament large 

 and dark brown ; epidermis yellowish or yellow green, with numerous green, 

 angular spots, with well marked not very distant marks of growth ; umbonial 

 slope raised, broad, with a depression anteriorly and posteriorly, each causing an 

 omargination at the margin ; posterior slope rather narrow, raised into a carina and 



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