20 



ed: suture moderately impresseil: body whirl yellowish, with two 

 equidistant rufous, revolving lines, of which the superior one is 

 much broader and its locality a little flatter than the general 

 curvature: aperture ovate, acute, above, moderately dilated: 

 labium with calcareous deposit, particularly above: labrum not 

 projecting near the base, nor arquatcd near its junction with 

 the second volution: base regularly rounded. 



Inhabits Falls of the Ohio. Length half an inch; breadth, 

 nearly a quarter of an inch. Var. a. Color dark brown; 

 bands obsolete. 



I found this species in great abundance on the rocky flats 

 at the Falls of the Ohio, where they w r erc left by the subsid- 

 ing of the river, in company with numerous other shells. In 

 old specimens the spire is very much eroded; the eroded part 

 is white. 



P ALU DIN A, Lam. 



P. transversa. Shell transverse, depressed, orbicular: spire 

 convex: whirls three and a half; with numerous minute, slight- 

 ly elevated revolving lines: suture not widely indented: body 

 whirl very convex, short: umbilicus small: operculum pale fulvous. 



Greatest width, two-fifths of an inch. Inhabits Louisiana. 



We obtained two specimens in the marshes near New Or- 

 leans. It is much wider in proportion to the length than any 

 other species I have seen, excepting in this respect even M. 

 subghbosa, Nob., and especially P. intertexta. Nob., of which 

 latter, in fact, I at first supposed it to be the young, in conse- 

 quence of its rotundity and the similarity of its capillary lines; 

 but inasmuch as the number of its whirls is nearly the same, 

 whilst the magnitude differs so greatly, I have separated it a9 

 a different species, 



P. intertexta, Shell subglobosc, yellowish-greenor brownish, 

 wrinkled, and with minute, very numerous, obsolete, revolving, 

 deciduous lines: spire depressed conic, obtuse, truncated, erod- 

 ed at tip: volutions nearly four: suture rather deeply indented: 

 umbilicus closed by the lateral extension of the columella. 



Greatest breadth, from four-fifths to one inch; length about 

 the same. Inhabits Louisiana. 



We collected many of these shells in the marshes near New 

 Orleans and on the banks of the Carondelet canal. It is re- 



