PLATE 116. 



Pag« 



Fig. 1-4. Plattceras nodosum. 473 



1 & 2. Casts of this species, preserving the usual form. 



3 & 4. View of the upper and lower side of the cast of a large individual. In this specimen, 

 the nodes, either from weathering or extreme age and thickening of the shell, are less 

 prominent than in the preceding. 



