^ \ 



UNI 0. 



Species 17. (Mus. Cuming-.) 

 Uxio TUAPEZOIDES. Lhu teslil ohlongo-trape:oided, 2)0B- 

 tice conspicue (umido-anr/iilalct, deiitde declivi-tnm- 

 cald, wnbonibus compressis, circa nmbones siibobsolete 

 crhpalo-verrucosd, peroMique breviter pUcato-costatd ; 

 epidermlde nigra. 

 Thk tkafezoid Unio. Sliell oblong-trapozoid, poste- 

 riorly conspicuously tumidly angled, then slopingly 

 truncated, umboes compressed, around the umboes 

 rather obsoletely crispately warted, very obliquely 

 shortly plicately ribbed; epidermis black. 

 Lea, Trans. Amer. Phil. Soc. vol. iv. pi. 3 ; Obs. vol. i. 

 p. 79. 



Unio iiderruptns, Say. 

 Hab. Lake St. Joseph, Louisiana, North America. 



Of a particularly characteristic trapezoid fonn, but par- 

 taking, nevertheless, of the sculpture of Z7. heros and its 

 congeners. 



Species 18. (Mus. Cuming.) 

 Unio aspek. Un. testa suI)quadrato-globosd, medio con- 

 cavo-coiitractd, postice obtuse aiigidaldet declivi-trun- 

 catd, biradiatini nodoso-tubercidatd, prope marginem, 

 posticum radiaiim rtigatd ; epidermide fidvo-olivaced. 

 The rough Unio. Shell somewhat squarely globose, 

 concavely contracted in the middle, posteriorly ob- 

 tusely angled and slopingly truncated, biradiately 

 nodosely tubercled, radiately wrinkled near the pos- 

 terior margin ; epidermis fulvous-olive. 

 Lea, Trans. Amer. Phil. Soc. vol. iv. pi. 9. f. 13 ; Obs. 



vol. i. p. 95. 

 Hnb. Alabama, North America. 



Besides the two conspicuous rays of tubercles noted 

 in the foregoing description, there are indications of pus- 

 tules which in some specimens may probably be more de- 



Spoeies 19. (Mus. Cuming.) 



Unio caPEU.^TUS. Un. testa oblongo-seciiriformi, antice 

 brevissimd, postice compresse prodnctd, concentrice ir- 

 regnlririter caperutd, medio olisolel'e radiaiim iioda- 

 latd fnho-oticaced, intense viridi ; radiatiin undidato- 

 lineatd. 



WRINKLED Unio. Shell ovately-oblong wedge- 

 shaped, anteriorly very short, posteriorly compressly 

 produced, concentrically irregularly wrinkled, obso- 

 letely radiately noduled in the miildle, fulvous-olive, 

 radiately undulately lineated with dark- green. 

 , Trans. Amer. Phil. Soc. Second Series, vol. .-c. pi. 

 5. f. 14; Obs. vol. iv. p. 49. 



Hub. Tennessee, North America. 



Extremely iiRnpiilateral, the shell being as short on the 

 anterior side as in Bonax. 



Tin 



Le.^ 



Species 20. (INIus. Cuming.) 

 Unio Elliottii. Un. testa suborbiculari, postice sublate 



expansu, oldique perampliler costald, postice radiatim 



costatd, umbonibus paroiuscidis ; epidermide nigra. 

 Elliott's Unio. Shell nearly orbicular, posteriorly ra- 



tiier broadly expanded, obliquely very largely ribbed, 



posteriorly radiately ribbed, umboes rather small; 



epidermis black. 

 Lea, Pro. Acad. Nat. Sci. Philadelphia, IS.V.. p. 20;^; 



.(ourn. Second Series, vol. iv. pi. 7 ; Obs. vol. vi. p. 



54. 

 Hub. Othcalooga Creek, Gordon County, Georgia. North 



America. 



A fine, bold spe 

 dar in form, thou 

 rior side. 



L'S of the r. heros 

 1 rather broadly t\\ 



August, 1S64. 



