GONIOBASIS. 251 



Description. — Shell conic, blackish, rather rapidly attenuated to an 

 acute apex ; suture not deeply impressed ; volutions about eight, but 

 little rounded ; aperture longitudinal ; within dull reddish ; labrum 

 with the edge not undulated, or but very slightly and obtusely so near 

 the superior termination. 



Length, three-fifths ; greatest breadth, three-tenths of an inch. 



Observations. — For this species we are indebted to Prof. Vanuxem, 

 who presented several specimens to the Academy. He informs me 

 that he obtained them in Virginia, in a stream running from Fig. 488. 

 Abington to the salt works, and from the stream on which 

 General Preston's grist-mill is situated, near the salt works, 

 as well as in a brook running through the salt water valley, 

 and discharging into the Holston River. Near the summit 

 the whorls are marked by an elevated line near their bases. 

 It cannot be mistaken for the conica (nobis) for in that species the 

 aperture is obviously oblique. — Say. 



The synonymy of the species indicated by the above table 



is due to the investigations of Professor Haldeman, whose 



fine suite of self-collected specimens demonstrates their entire 



identity. Figure 488 is from an author's example of simplex 



in Museum Anthony. I have specimens of the same form, but 



of much larger size. Warderiana is figured from Mr. Lea's 



plates. 



The following are the descriptions of the synonymes : — 

 t 



Mdania Warderiana. — Shell cariuate, club-shaped, rather thick, 

 ver}' dark; spire conical; sutures linear; whorls eight, convex; ap- 

 erture ovate, rather large, within flesh-color. 



Habitat. — Cedar Creek, a branch of Clinch River, Russell County, 

 Virginia. 



Diameter, -37 ; length, -76 of an inch. 



Observations. — I have two specimens before me. The two lowest 

 Fig. 489. whorls ai'c smooth, the superior ones are carinate, with a 

 small, intermediate stria, the upper whorls diminish very 

 rapidly. The exterior of the shell is very black and shining, 

 and its color appears to arise from a deposit of ferruginous 

 matter, as the substance of the shell is reddish. The aper- 

 ture is rather more than one-third the length of the shell. 

 I name it after Dr. "Warder of Cincinnati, to whom I owe the posses- 

 sion of this and other interesting specimens. — Lea. 



