EXPLANATION OF PLATE XLYlI. 



Belemnitella Americana Morton (p. 280), 



Figs. 1,2. Views of the opposite sides of a small individual figured by Dr. Morton in his Synopsis 

 under the name Belemnites subfusiformis. Acad. Nat. Sci., Phila. 



3. View of a heavy thickened specimen much rounded at the. base. Rutgers College. 



4. A smaller specimen, showing the mucTonation at the base. Eutgers CuUege. 



5,6. Two views of a very large individual presenting the usual form. Kutgers College. 



7. View of part of the same after having been split hingiludinally. 



8. View of a small specimen imperfect at the lower end, but preserving the walls of the 



cavity out to a thin margin. Am. Mus. Nat. History. 



9. View of the filling Qf the alveolar cavity of the last specimen, showing the thickened ridge 



on the cast on the side opposite to the slit in the stylet. 

 10, 11. Views of a phragmocone showing the septa! markings, Rutgers College. 

 392 



