UN 10 



Species 165. (Mils. Cuming,) 



Unio negatus. Un. lestd snhquailratd, irniisverise ml- 

 catd, coiiipri'ssd, subaquilatL'rali, mtus alba vd snb- 

 rosaced, aiitice hrevimrula, rotunda, poaflce aiKjulaid, 

 pod angidnm plana, anlf nngidinii pitiiluhtui excti- 

 vatd, niiibonibiis rityiilosis. 



The unacknowledged Unio. Shell suljunadratc, Iruns- 

 versely siilcated, compressed, subequilateral white 

 or slightly rose-tinted within, rather short, rounded 

 in front, angulated at the back, flat behind the 

 angle, slightly excavated in front of the angle, um- 

 boes rugose. 



Lea, Unio viii. p. 80. pi. ix. f. '2e.j. 



Jlab. Big Prairie Creek, Alabama ; E. R. iShowalter. Co- 

 lumbus ; Miss Spillmau. 

 Dr. Lea states the ditt'erence between this species and 



his IL ruhigiiiosiis to be, that in the latter the wrinkles 



on the region of the uniboes are numei'ous and spread, 



while those of the former are confined to two or three 



on the posterior side. 



Species 10(i. (JIus. Cuming.) 



Unio henosus. Ua. tcsid iiijlald, subelongalo-ovall, siil- 

 ciifd, iiitits roseo-piirptirascente, exlus fused, obscure 

 radiatd, latere antico breci, rotimdo, medio subdeprem<i, 

 margiiie subexcavato, latere podico injlato, obscure fri- 

 angulato, margiiie terminali acnminato. 



The swollen Unio. Shell inflated, subelongately-oval, 

 sulcated, purplish-rose within, brown, obscurely ra- 

 diated without, anterior side short, round, slightly 

 depressed in the centre and excavated at the margin, 

 hinder side inflated, obscurely triangulated, with the 

 terminal margin pointed. 



Conrad, in Sillimau's Journal, vol. xxv. t. L f. 4. 



Hub. River Alabama. 



Of an elongate, oval form, ecpially inflated throughout. 



Species 167. (Mus. Cuming.) 

 Unio Suuttlewoktui. Un. teddeloiujulo-subtrapezoided. 



iiitiis purpurasceute, extits valide ruguloso-sulcafd, aii- 

 tice brevi, augustd, rotuiidd, podice dongatd, lata, ro- 

 luiidatiiii mbangulatd, margiiie veiitrali recliuscido, 

 margiiie dorsali podice elevato, subalato, margiiie ter- 

 minali obliquo, medio sulexcavato. 



Shuttlewokth's Unio. Shell elongately-subtrapezoidal, 

 purplish within, strongly rugoscly sulcated without, an- 

 terior narrow, short, round, posterior elongated, broad, 

 roundly subangular, ventral margin rather straight, 

 dorsal margin elevated, and subalate posteriorly, ter- 

 minal margin oblique, subexcavated in the midille. 



Lea, Unio vi. p. 34.. pi. xxix. f. IS). 



llab. Australia; Shuttleworth. 



ipi)earanee of 



Iridiua Nilut/ca. 



^pecles 



(Mus. Cuming.) 



Unio i'olitus. C/it. tedd oblique ocatd, erassd, iiitus ulbd, 

 extus fiiico-lutesceiUe, didanter sulcata, aiitice breois- 

 siiud, iiiargiiw dorsali angidato, podice oblique elon- 

 gatd, subdilatatd, complumdd, obscure biaugidald, uuir- 

 gine dorsali declivi. 



The polished Unio. Shell obliquely-ovate, thick, white 

 within, yellowish-brown, and distantly sulcated with- 

 out, very short in front, with the dorsal margin au- 

 gulated, obliquely elongated at the back, slightly di- 

 lated and flattened, obscurely biangulated, with the 

 dorsal margin sloping. 



Sav. 



Ilab. River Ohio. 



A remnrkalily oblique species, with very short front. 



Species lU'J. (Mus. Cuming.) 



) BuRROUGUIANUS. O'u. tesid ooali-obliiugd, obtiijuii, 

 siiUdd, coiiceutrice irreyulariler sulcata, iutus alba, 

 extas epidermide viridi nigresceute, ad umboiies el ver- 

 sus medium oblique aiigidatiin et divariratnu riigatd. 



late 



Htico br 



ubrutuudu, latere pt 



eluiigatu 



