34 Bui^ivETiN 5 304 



128 FOSSIL SHELLS. 



ceeding whorls: body whorl with four belts, which 

 are equidistant, much elevated, wider at top than 

 at the junction with the whorl* and with one or 

 two deeply impressed lines ; intervening spaces 

 wrinkled, the wrinkles extending over the belts : 

 aperture suboval : canal short and contracted : la- 

 bru-m with a groove corresponding with each of 

 the exterior ribs : umbilicus dilated, large, not visi- 

 bly penetrating to the inner summit ; the exterior 

 margin prominent and deeply dentated. 



Varies much in size ; the smallest in Mr. Finch's 

 collection is about three-fifths of an inch wide, 

 another is rather more than one inch in width, 

 and the largest is nearly three inches and three- 

 fourths ; but a fragment of a still larger one leads 

 me to believe that the species attained to a width 

 of more than four inches. I am unable to state 

 the proportional length, all the specimens having 

 truncated spires. The belts of some young spe- 

 cimens are altogether destitute of the impressed 

 lines. 



It seems hardly possible that Leister's figure 2, 

 of plate 1059, was intended for this shell, although 

 it has certainly a general similarity in the ribbed 

 appearance of the figure, and notwithstanding the' 

 locality "« Maiylandia,'' which is engraved with 

 it, inasmuch as there is not any appearance what- 

 ever of an umbilicus, which is so much dilated and 

 so remarkable in the species under consideration. 



Lister's figure is quoted by several authors 



[J. A. N. S., Phila., ist Ser., Vol. IV, 1824.] 



