Plate 5. 



Fifi. 1. Aniinodisciis ijtrertua. X 1'*, inicrospheriL' form, a, eido view; l>, apertural 

 view. 



2. Ammodiscv.s vicerfuti. X 10. ^legalospherir form. 



3. Ammodiscus i^ircrtux, yar. flisenideus. X 10. «, side view, /;, apertural view. 



Microspherif form. 



4. Ammodiscns erseitu-;. X 13. 



494 



