LAND AND FKESH-WATEIi SHELLS OF N. A. [PART IV. 



SPECIES. 



A. Shell smooth or only slightly tuherculate. 

 1. I. fluvialis. Say. 



Fums flm-inlls. Sat, Jonr. Acad. Nat. Sci., t, p. 129, Nov., 1825. Conrad, New 



Fresh- Water Shells, p. 12, 1834. 

 JofluiiaUs, Say, Binxey, Check List, p. 12, June, ISGO. 

 lo jluridiiUs, Say, Woodward, Manual, t. 8, f. 27. Haxlet, Conchological Misc. 



Mclania, t. 6, f. 50. Reeve, Monog. lo, 1. 1, f. 5. H. & A. Adams, Genera, i,299. 



Brot, Cat. des Melauiens, p. 29. Brot, Malacol. Elatt, ii, 114, 1860. 

 Pleurocera fluvialis, Say, Haldeman, Iconog. Encyc, ii, p. 84. 

 lo fusiforniis, Lea, Philos. Trans., iv, p. 122, 1. 15, f. S7a,b; Observations, i, p. 132, 



1. 15, f. 37a, b. Ravenel, Catalogue, p. 11. Troost, Catalogue Shells of Ten- 

 nessee. Chexu, Man. Conchyl., i, f. 1977. DeKay, Mollnsca New York, p. 103. 



Wheatley, Cat. Shells U. S., p. 28. Say, Catalogue, 4th edit., p. 277. Reeve, 



Monog. lo, 1. 1, f. 6. 

 lo tcHcbrosa, Lea, Philos. Proceedings, ii, p. 34, April, 1841; Philos. Trans., ix, p. 



17; Observations, iv, p. 17. Wiieatlev, Cat. Shells U. S., p. 29. Bikxey, 



Check List. No. 404. H. & A. Adams, Genera, i, 299. 

 lo verrucosa. Reeve, Monograph lo, 1. 1, f.2, April, 1860. Brot, Cat. des Mela- 



nieus, p. 29. 



Description. — Shell fusiform, olive-green or brownish; spire much 

 elevated, gradually tapering; volutions nearly six, ■wrinkled across, 



and with a series of elevated un- 



rig. 26. 



Fig. 27. 



dulatious on the middle ; suture 

 consisting only of an impressed 

 line; aperture somewhat fusiform, 

 w'ithiu whitish, more or less with 

 dull reddish, and with several lines 

 of that color sometimes confluent; 

 labrum on the inner margin im- 

 maculate, edge undulated ; canal 

 rounded at tip ; columella very 

 concave. 



Length, 1 8-10 inches; aperture, 

 19-20 of an iuch ; greatest breadth, 

 19-20 of an inch. 

 Observations. — Professor Vanuxem found this curious and highly in- 

 teresting shell (Fig. 27) on the north fork of the Holston River, near 

 the confluence of a brook of salt w^ater. From the name of the genus 

 it might reasonably be supposed to be a marine shell, but it has never 

 been discovered on the coast, and seems to be limited to a very small 

 district of the Ilolston IJiver, in company with Unio carivs^is, sub- 

 tentus, nobis, Melania siibglobosa, nobis, and no doubt other fluviatile 



