Call — The Unionidce of Arkansas. 51 



listed in this register. Recently a large set of some twenty 

 specimens was received from Carney Bayou, Claiborne Par- 

 ish, Louisiana, rendering it very likely that the shell will yet 

 be found abundantly in favorable localities in Arkansas. 

 Some years since the writer collected it, in large numbers, in 

 Piney river, Texas county, Missouri. It groups with Barnes 

 form, along with Unio sublatus Lea, though the specific value 

 of all the forms is doubtful, the point cannot be settled now. 

 The specimens from Louisiana and Missouri have been com- 

 pared with large suites from the Oostanaula river, collected in 

 1881. They difi*er in no respect. 



Unio subrostratus Say. 



New Harmonv Disseminator of Useful Knowledore, 

 January 15, 1831; reprint by Say, p. 6. From the 

 Wabash river. The shell which Reeve figures for this 

 species, Conchologia Iconica, Vol. XVI, Unio Plate 

 XVII, Fig. 78, is Unio iris^ and was drawn from a speci- 

 men communicated by John G. Anthony, who, evidently, 

 did not know the species. 



Unio nashvillianus Lea. Trans. Am. Philos. Soc, Vol. 

 V, 1834, p. 100, PI. XIV, Fig. 43; Reeve, Conchologia 

 Iconica, Vol. XVI, Unio Plate XXX, Fig. 158. De- 

 scribed from specimens communicated by Dr. G. Troost 

 from the Cumberland river, at Nashville. See below. 



Unio mississippiensis Conrad. Jour. Acad. Nat. Sci. 

 Phila., 2d series, 1850, p. 277, PI. XXXVIII, Fig. 11; 

 Reeve, Conchologia Iconica, Vol. XVI, Unio Plate XIX, 

 Fig. 85. Described from the lower Mississippi. 



Unio nigerrimus Lea. Trans. Am. Philos. Soc, Vol. 

 X, 1852, p. 268, PI. XVin, Fig. 23. From Alexandria, 

 Louisiana. 



UniorutersvillensisLiea,. Jour. Acad. Nat. Sci. Phila., 

 2d series, Vol. IV, 1860, p. 356, PI. LX, Fig. 181. 

 Described from Rutersville, Fayette county, Texas. 



Unio topekaensis Jjea.. Jour. Acad. Nat. Sci., 2d series. 

 Vol. VI, 1868, p. 313, PI. XLIX, Fig. 126. Described 

 from near Topeka, Kansas. 

 Specimens were secured from the White river, Carroll 



