80 PROCEEDINGS OF THE ACADEMY OF [IcSy.). 



they cross the revolving ridges. Aperture narrow, ovate, outer lip 

 thick, and deeply notched, lobe acute, inner margin crenulated by 

 about twenty short ridges; inner Up thin, expanded, bearing a rugose 

 callous ridge which curves gradually downward toward the posterior 

 end of the aperture, above which, at the posterior commissure is 

 a small rugose triangle, the posterior canal extending to the base of 

 the fourth spiral whorl. Length 20 mm., greatest diam. 9 mm. 



One specimen from the material collected by Thomas A. Morgan, 

 at Jackson, Miss. 



Potamides (Telescopium) chamberlaini n. sp. Plate II, fig. 11. 



Shell acute (apex wanting), whorls flat, slightly concaved orna- 

 mented by revolving rows of nodules, one above and a double or 

 geminate row below the suture, on the body Avhorl the nodules 

 become obsolete on the periphery, on the spiral whorls between the 

 nodules are from two to four revolving ridges and on the body 

 whorl six, just below the periphery is a prominent low ridge with 

 two small raised lines between it and the periphery, the base ot the 

 shell is covered with numerous minute revolving lines; columellar 

 fold at the base broad, rounded and carinated on the lower edge, 

 a break on the second spiral whorl shows that the same is there 

 narrow and sharply keeled. Length of the specimen figured 35 

 mm., greatest diam. 14 mm. 



Two specimens collected by Mr. Frank Burns, from the Midway 

 Eocene, at Matthew's Landing, Ala. 



This beautiful shell is named in honor of Rev. L. T. Chamber- 

 lain, D. D., to whose untiring interest and generous aid the pres- 

 ent status of the ' ' Isaac Lea Collection of Eocene Mollusca ' ' 

 is due. 

 AmpuUina morgani n. sp. Plate II, fig. 12. 



Shell globose, spire prominent, whorls convex, somewhat flat- 

 tened below the suture, smooth, with numerous, very close, fine 

 lines of growth, and obsolete revolving raised lines on same portion 

 of the shells, umbilicus of moderate width surrounded by a reflected 

 polished callus, that extends to the anterior portion of the aper- 

 ture, pillar-lip thin not reflected over the umbilicus. Lengtli ol 

 mm., greatest diam. 27 mm. 



Two specimens collected by Thomas A. Morgan, at Jackson, Miss. 



This species is distinguished from A. streptostoma Heilp. by the 



