19 



situations than any other species, particularly in the vicinity 

 of the Falls of the Ohio. 



It may readily he mistaken for a young shell. 



M. isogona. Subglobose, horn color: volutions ahout four, 

 rounded, obsolctely wrinkled: spire very short, about one-third 

 the length of the aperture: suture profoundly impressed, so as 

 to cause a shoulder on the whirls: aperture much dilated, oval, 

 being as obtusely rounded above as at base: umbilicus linear, 

 distinct: operculum obviously spiral. 



Length, under three-tenths of an inch. Inhabits Bear-Grass 

 Creek, near Louisville. 



Not very numerous. It is remarkable by the oval form of 

 the much dilated aperture, and by the deeply indented suture. 

 In old specimens, the base is almost acutely angulal 



M. trilineata. Subglobose oval, yellowish, more or less tinged 

 with brown: volutions about four, rounded, somewhat wrinkled: 

 spire short, rather more than half the length of the aperture: 

 suture not very deeply impressed : burly whirl w ith three brown- 

 ish black revolving lines, of which the two inferior ones are 

 somewhat nearest together, the middle one widest, and the 

 superior one placed near the suture and revolving on the spire; 

 the middle one is concealed on the spire, by the suture: aper- 

 ture much dilated, ovate, acute above: labium a little flatten- 

 ed: labrum widely and regularly rounded, without any protru- 

 sion near the base: bast slightly angulated, without any sinus 

 or undulation: umbilicus none. 



Inhabits Falls of the Ohio. Length, less than half an inch. 

 Var. a. Inferior band obsolete. Var. b. Bands obsolete. 



This species is allied to the preceding, but is obviously dis- 

 tinct in its general appearance; the volutions are destitute of 

 a shoulder, and the aperture is ovate, acute above. It i^ a 

 pretty shell, the bands being very conspicuous, strongly con- 

 trasting with the yellow general color, particularly in the 3 

 and half grown shell. 



I obtained about a dozen specimens on f flats of 



the Falls of the Ohio, at the lower end of the island which is 

 nearest to Louisville. 



M. depygis. Shell oblong conic ovate, not remarkably thick 

 ened: spire as long a-< the apertui her longer, much 



eroded, with a broad revolving hand near the suture, 



ine: more than half th- «"" %r are: whirls about five, hardlj round 



