U N I . 



Plate XVI 1 1. 



Species 81. (Miis. Cumins.) 



Unio depressus. Ua. iedd ovali, nfrhiqne rotiindatd, 



concentrice rude riigatd, latere posltco laliore ; nigri- 



cante-fuscd. 

 The depressed Ukio. Slull ovnl, rounded at each end, 



concentrically ru<lel_v wrinkled, posterior side broader; 



blackish-brown. 

 L.\MARCK, Anira. sans vert. vol. vi. p. 5 tk 



Unio Baloiieiisis, Conrad. 

 Ilab. Australia. 



A shell of simple oval form, moderately convex, of which 

 the posterior side is rather the broader. 



Species 82. (Mus. Cuming.) 



Unio perdix. Uh. testd ohUque ovald, roiiijiressiiisc/iM, 

 anlice subabbreviatd, rotuudutu, postice declke subai- 

 tenuato-prodiictd ; hdescente-olwaced, intense viridi 

 copiose tatiradiatd. 



The partridge Unio. Shell obliquely ovate, rather 

 compressed, anteriorly rather shortened, posteriorly 

 slopingly rather attenuately produced ; yellowish- 

 olive, copiously broadly rayed with dark-green. 



Lea, Trans. Amer. Phil. See. ii>'ii ; Obs. vol. i. p. 1S4-. 

 pi. 11. f. 31. 

 Unio pectorosiis, Conrad. 



Hah. Tennessee, North America. 



A prettily-rayed species of very regul 



rowth. 



Species S;?. (Mus. Cuming.) 

 Unio vittatus. Un. testd subquadraio-ovntd, xuhob- 

 liqud, teniii, antice rotiindatd, postice siihqiiiidrato-ex- 

 pansd, iriinattd, lavigatd, nitente, creberrime concen- 

 trice fdo-striatd ; sordidefuloo-olivaced. 

 The filleted Unio. Shell somewhat squarely ovate, 

 rather oblique, thin, anteriorly rounded, posterioriy 

 somewhat scjuarely expanded, truncated, smooth, 

 shining, very closely concentrically thread-striated, 

 didl fulvous-olive. 

 Lea, Pro. Acad. Nat. Sei. Phil. 1S50, p. 153; Obs. vol. 



vii. p. i;7. pi. 38. f. 12S. 

 Ilab. Australia. 



A thin ^HOf/w«-likc .species of a peculiar dull fnlvon- 

 olive colour, sculptured throughout with close-set con- 

 centric thread-like strise. 



Species 81-. (Mns. C\uning.) 

 Ukio obesus. Un. testd ollongo-lrupezoided, yibhosiiis 



cii/d, antice brevissimd, rolundatd, postice declive quad- 



rato-angutatd, trtincatd, olivaceo-uigrd, epidennidt 



rngoso-striatd. 

 The stout Unio. Shell oblong-trapezoid, rather gib 



bous, anteriorly very short, rounded, posterioi'l} 



slopingly quadrately angled, truncated, 



epidermis rugosely striated. 

 Lea, Trans. Amer. Phil. Soc. 1830 ; Obs. va 



pi. 13. f. 2G. 

 Ilab. York Eiver, Virginia, North America. 



A coarsely-striated shell, nnuli prodneed 

 into a sloping truncated angle. 



.ck. 



Liber, 18(;4. 



