EXPLANATION OF PLATE XLIIL 



Ammonites Delawarensis Morton (p. 252). 



Figs. 1,2. Lateral and profile views of a large sjiecimen from the collection of the Acad. Nat. Sci., 

 Phila. The diagram of a septum, Fig 9 on PI. xliii, is from the outer part of this 

 specimen, 

 3d4 



