PLEUROCERA. 55 



equally impressed baud ; iuferior bouudary of the band elevated aud 

 deeply crcnate ; superior bouudary elevated and some- Fig. 105. 

 times nodulous; volutions at least eight, not convex; 

 suture not impressed, hardly obvious, undulated by 

 revolving on the iuferior creuate boundary of the im- 

 pressed band; labrum near the base, much protruded; 

 sinus very obtuse. 



Habitat. — Ohio River. 



Length one inch and four-tenths. 



Observations. — I observed this large species to be 

 abundant in Kentucky River, when travelling in that 

 state two years since with Mr. Maclure. It seems to 

 approach nearest in character to the canaliculata, nob., 

 but its rough appearance will distinguish it even at first sight. — Say. 



A fine specimen from Mr. Anthony's collection is the original 

 of our figure. 



The various species of this general t3-pe, described by Mr. 

 Lea, nobilis, moniliferum, nodosum, are not sufficiently distinct. 

 This shell may (for the present) remain separated from them 

 on account of the sulcate baud encircling the periphery and 

 its being wider. 



This species extends through Ohio, Indiana, Illinois, Ken- 

 tucky, Tennessee, Alabama, and West Georgia and presents 

 great variation of contour. The number of nodules on the 

 periphery varies, and also the development of the canal. Many 

 of the large specimens, broadly banded, are very beautiful. 



4. P. excuratum, Conrad. 



Melanin excurata. Conrad, New Fresh-Water Shells, p. 49, t. 4, f. 0, 1834. AXTIIOXT, 

 List, 1st and 2d edits. Jav, Cat., 4tli edit., p. 273. DeKay, Moll. N. Y., p. 96. 

 BiNXEY, Check List, X6. 103. MIU.lek, Synopsis, p. 43, 183G. 



Melanin excurvata, Conrad, Wheatley, Cat. Shells U. S., p. 25. 



Melanin rorata, Reeve, Monog. Mel., sp. 306. BuOT, List, p. 31. 



Jo Spillninnii, Lea, Proc. Acad. Nat. Sci., p. 394, 1801. Jour. Acad. Nat. Sci., v, pt. 

 3, p. 348, t. 39, f. 215. Obs., ix, p. 170. 



Description. — Shell subulate, with a spiral band of slightly oblique 

 subcorapressed tubercles on the base of the inferior whorls ; above 

 this is a prominent line with slight intervening channel, volutions 

 towards the apex nearly entire; base with three prominent lines, 

 the superior one largest; the third hardly prominent and approximate 

 to the middle one. 



