U NIO 



Vla 



Species 13. (.AIus. Cuming.) 



Unio ATR0C0ST.4.TUS. Un. tes(d ovatd, oblique subjlahelli- 

 fond, circa umbones irregulariter crispaio-nigatu, de- 

 inde oblique ampUter plicato-costatd ; epidermide nigra. 



The black-ribbed Unio. -Shell ovate, obliquely some- j 

 what fan-shaped, irregularly crispately wrinkled 1 

 around the umboes, then obliquely largely plicately 

 ribbed ; epidermis black. 



IjEA, Trans. Amcr. Phil. See. Second Series, vol. 10. pi. j 

 2. f. 5 ; Obs. vol. 4.. p. -l-i. 



Hab. Alabama, North America. 



There is very little in this species, beyond the fact of I 



its being of a less oblong-square form, to distinguish it 



Species 14. (Mus. Cuming.) 



Unio sparsus. Un. testa suborbiculari-ovaid, depressd, 

 postice obtime angulaid et Jiexiioso-conipresm, laviiis- 

 culd, obsolete sparsim verrucosa, poslici subverrucosd ; 

 epidermide ftdvo-oUvaced. 



The sprinkled Unio. Shell somewhat orbicularly 

 ovate, depressed, posteriorly obtusely -angled, and 

 ttexuously compressed, rather smooth, obsoletely 

 sparingly wartetl, posteriorly rathei- warted ; epider- 

 mis fulvous-olive. 



Lea, Trans. Amcr. Phil. Soc. Second Series, vol. 8. pi. 

 25. f. 58 ; Obs. vol. 3. p. 82. 



Hab. East Tennessee, North America. 



Very similar in form to IT. tubercuhifus, and not 



unlike the young of that species. 



luch 



Species 15. (ilus. Cuming.) 



Unio Phillipsii. Un. testa ohhmyo-quadratd, medio 

 subcontractd, postice peranipliler expnusd, biangulatd, 

 ad angulos et versus marginem promiscue lumido- 

 tuberculatd ; epidermide virescenle, olivaceo radialim 

 fasciatd et lineatd. 



Phillips' Unio. Shell oblong-square, rather contracted 

 in the middle, posteriorly very largely expanded, 

 two-angled, promiscuously tumidly tubercled at the 

 angles and towards the margin ; epidenuis greenish, 

 radiately banded and lineatcd with olive. 



Conkad, Monog. p. 9. pi. 5. f. 1. 



Hub. North America. 



Characterized by an unusual expansion of the posterior 

 side, which is bi-angled, and rudely tumidly tubercled on 

 the angles. 



Species 16. (Mus. Cuming.) 



Unio costatl's. Un. testa oblotigo-ovatd, postice subquad- 

 rato-productd, medio oblique sinuose plicato-costatd, 

 cos/is versus marginem poslicum corrugaio-radiantibus; 

 epidermide fulvo-olivaced. 



The ribbed Unio. Shell oblong-ovate, posteriorly ra- 

 ther squarely produced, obliquely sinuously plicately 

 ribbed in the middle, ribs corrugately radiating to- 

 wards the posterior margin ; epidermis fulvous-olive. 



Rafinesque, Mon. Coq. de la riv. Ohio, Ann. Gen. Sc. 

 Phys. Brux. 1830, vol. 5. p. 28 7. 

 Uuio undulatus, Barnes. 

 North America. 



IM 



This species appears to differ from its congeners in not 

 being crispately warted about the umboes. 



