UNIO.— Plate LXXXII. 



Magk depressd el rostd nmhoiiali tiibercidoriim ex- 



perle. 

 Ward's Unio. Shell extremely like JJ. melanever, but 



more depressed, and with its iiinboiial ridge devoid 



of (the characteristic) tubercles. 

 l.EA, Proc. Ac. N. S. Philad. 1861, p. 392: Obs. on 



Unio, vol. ix. p. 9. pi. 24. f. 257. 

 Hnh. Ohio, Iowa, and A'irginia, N. America. 



A somewhat doubtful species, but worth figuring, from 

 its great dissimilarity to the ordinary examples of vieta- 



Species 435. (Mus. Lea.) 

 lo Spjllmannii. Vn. testa magna, subaqidlateraU, 

 iiibcrasm, irijlatd, oblongd, anlice porrectd et angmle 

 rnimidatd, postiee sitbbiangidatd, mlidd, Icer'ujuld, 

 fiisco-rnfesceide, vel fiisco-nigresceute, obsolete railicitd, 

 iiinrglne venlrali hand retuso ,- casta iimbonaU rotiiii- 



datu, emineute ; limnld vel angustd, vel nulla, vmbo- 

 nibus eiuinenllbiis, ad apices nigoso-undulaiis ; mar- 

 garitd alba; dentibus cardinalibus parvis, tubercu- 

 lato-coiii/jressii, in utrdque valvuld singulis ; denlib/m 

 lateralibiis nidlis. 



Spillman's Unio. Shell large, subequilateral, thickish, 

 swollen, oblong, projecting and narrowly rounded in 

 front, almost biangular behind, smooth, shining, 

 from reddish to very dark brown, obscurely rayed, 

 not indented at the ventral margin ; umbonal ridge 

 rounded and prominent ; lunule, if any, narrow ; 

 umboes projecting, rugosely undulated at the tips ; 

 nacre white ; primary teeth small, compressed-tuber- 

 cular, one in each valve ; no lateral teeth. 



Lea (Margarita, I a), Proc. Ac. N. S. Philad. 1858, p. 

 138; Obs. on Unio, vol. viii. p. 109. pi. 17. f. 252. 



Ilab. Tombighee river, Mississippi. 



The hinder slope has two raised lii 

 l)eak.s. 



running from the 



