U N I 



Species 265. (Mus. Cuming in Brit.) 



Unio Myersianus. Un. testa ovoli, comjiresna, expmm, 

 alatd, tentii, Itevigotd, fiisco-Jluvidd, fasciaid, i/ilm 

 purpurea ; latere postico magna, expamo, hiancjulato, 

 margme dormli elevato, tortiio, termino trmicato, tnnr- 

 gine ventrali ante angulum convexo, antice snrsum 

 nccUvi; latere aiitico brevi, angnsto, margiiie dorsali 

 alato. 



Myees's Unio. Shell oval, com pressed, expanded, 

 winged, tbin, smooth, yellowish-brown, banded, 

 piu-ple within ; posterior side large, expanded, bian- 

 gular, with dorsal margin elevated, tortuous, trun- 

 cated at the end, ventral margin convex in front of 

 the angle, anteriorly sloping upwards ; anterior side 

 short, narrow, dorsal margin winged. 



Lea on Unio, vol. vi. p. 9. pi. 21. f. 1. 



Hat). Camboja, Lao Mountains. 



The tortuous dorsal margin of the posterior wing, and 

 the existence of the small anterior wing, distinguish this 

 species from U. alattts. 



Species 266. (Mus. Cuming in Brit.) 



Unio complanatus. U/i. testa subovali, compressd, 

 rrassd, iiiargine dorsali et medio plicis magnis diver- 

 geutibiis iindato, inius albo, dentibus crassis ; latere 

 postico magno, elevato, alato, oblique biangulato, mar- 

 gine ventrali ante angulmn acclivi, turn convexo, me- 

 dio rectiusculo ; latere atitico brevi, declivi, umboni- 

 bns miflnlatim plicalis. 



The flattened Unio. Shell suboval, compressed, 

 thick, at the dorsal margin and in the centre undu- 

 lated with large diverging plaits, white within, teeth 

 thick; posterior side large, elevated, winged, ob- 

 liquely biangular, ventral margin in frout of the 

 angle sloping upwards, then convex, rather straight 

 in the middle; anterior side short, sloping, umboes 

 wavily plaited. 



Barnes, Lea on Unio, vol. i. p. 62. 



Hab. Ohio. 



Much less expanded than U. Ciiutingii, and diffei'ently 



plaited. 



November, 1866. 



