UXIO.— Platk xxxvir. 



niiirgiu, posterior side lon^v tiimiJ. v; 



umboes large, inflated, sniootli. 

 Lea, Unio ii. p. 14. pi. vi. f. 14. 

 IM. Teche River. Louisiana ; \V. M. Sle 



A verv lull, riluniii sli.-ll, v.-rv beaulii 



Species 304. (Mus. Cuming.) 



Unio augenteus. Un. Icstdsubctineatd, perMiquu, rrassd, 

 compressd, in/iis albd, exlus fusco-luleicei/te, jjosiice ra- 

 diaiim nip'o-maciilatd, latere ant'tco brevissimo, tumido, 

 siiblniiwnto, medio depresso, latere poMico angulnto, nd 

 termiinnii acnminato, area podaiujalari cnKjtintd, de- 

 rlici. 



The silvery Unio. Shell somewhat wedge-shaped, very 

 oblique, thick, compressed, white inside, yellowish- 

 brown outside, rayed at the back with black spots, 

 anterior side very short, tumid, sliglitly truncate, 

 middle depressed, posterior side angulated, acumi- 

 nated at the end, post-angular area narrow, sloping. 



Lea, Unio iii. p. 80. pi. 23. f. 26. 



Hah. Holston Kiver, East Tennessee; Dr. Troost. 



Dr. Lea obsfrves that this species resembles U. ovi- 



fvniih, Conrad, but 

 much darker colour. 



Species 205. (Mus. Cuming.) 



Unio dolabelloides. Un. te.itd brevi, nlbd, crasm, 

 cuueald, iida.s albd, extus distniiler sulcata, fused, nigra 

 radlatim macidatd, latere aiitico brevissimo, suhtrun- 

 cato, tumidij, margitie ventraU rotundo, latere pontiro 

 arcuatim biaiigulato, ante augidniii prim urn depresso, 

 ad ierminiim acuminato, area postangularl anyustis- 

 siiiid, declivi, itmbonibus magnis, tnmidis. 



The hatchet-shaped Unio. Shell short, elevated, 

 thick, wedge-shaped, white within, distantly sulcated, 

 brown, rayed with black spots, anterior side very 

 short, rather truncated, tumid, ventral margin round, 

 posterior side with two arched angles, depressed in 

 front of the first angle, acuminated at the end, post- 

 angular area very narrow, sloping, umboes large, 

 sloping, tumid. 



Lea, Unio iii. p. 53. pi. xv. f 31. 



Ilab. Holston River, Tennessee ; S. N. Edgar. 



This shell is one of the cuneatc forms of the genus. It 



is marked with a single row of black spots on the tumid 



posterior ridge. 



