316 NEW UNIONID^, MELANID^, ETC. 



Remarks. — A single specimen only was sent by Dr. Showalter to Dr. Lewis, who 

 kindly sent it to me. It does not seem to have been before observed. It cannot well 

 be confounded with any other species. It is much more lenticular than any other 

 nodulous TInio with which I am acquainted. It is allied to pustulosus and turgidus 

 (nobis), but differs much from them both. The specimen before me is nearly in the 

 form of a thick lens, and covered with nodules except on the anterior and anterior- 

 basal portions. The nodules on the posterior slope run into lines towards the margin. 

 It is not high in the beaks as lyusiulosus, nor has it the broad green rays which that 

 and turgidus have. The teeth are remarkably robust. 



Unio planioe. pi. 50, fig. 129, 



Testa subsulcata, subtriangulari, ad latere planulata, intequilaterali ; valvulis crassiusculis, antice 

 crassioribus ; natibus subprominentibus ; epidermide vel lutea vel ochracea, radiata ; dentibus 

 cardinalibus parvis, compressis striatisque ; lateralibus longis, crassiusculis et obliquis ; margarita 

 alba et iridescente. 



Shell subsulcate, subtriangular, flattened at the sides, inequilateral ; valves a 

 little thick, thicker before; beaks somewhat prominent; epidermis yellow, or 

 ochraceous and radiate ; cardinal teeth small, compressed and striate ; lateral teeth 

 long, somewhat thick and oblique; nacre white and iridescent. 

 Proc. Acad. Nat. Sci. 1868, p. 145. 



Hah. — Tennessee, Mr. H. Moores; head-waters of Holston Eiver, "Washington 

 County, Va., Prof, Cope. 



My cabinet and cabinets of the Academy of Natural Sciences and Mr. Moores. 

 Diam. -8, Length 1-5, Breadth 2-3 inches. 



Shell somewhat sulcate, subtriangular, flattened at the sides, inequilateral, sub- 

 biangular behind and rounded before ; substance of the shell a little thick, thicker 

 before ; beaks somewhat prominent ; ligament rather thick, short and light brown ; 

 epidermis yellow or ochraceous, with broad maculate rays and with rather distant 

 marks of growth ; umbonial slope slightly raised and flattened ; posterior slope 

 narrow elliptical, carinate, with an impressed line from the beaks to the posterior 

 margin ; cardinal teeth small, compressed and striate ; lateral teeth long, somewhat 

 thick and oblique ; anterior cicatrices distinct, large and well impressed ; posterior 

 cicatrices confluent, large and slightly impressed ; dorsal cicatrices placed above the 

 centre of the cavity of the beaks; cavity of the shell shallow and wide; cavity of 

 the beaks somewhat deep and angular ; nacre white and iridescent. 



BemarJcs. — The specimen from Mr. Moores has been in my possession for some 

 time ; from what river it came is not known. Recently Prof. Cope has brought the 

 same species from the head-waters of the Holston, which, although dead and imper- 



