366 Review of some recent American 
sacrificed to effect. He who would adopt the theory that 7i- 
gonellites or Aptychi are the opercula of Ammonitidz and Goni- 
atitidse, must first admit that the jaws of those animals have 
never been discovered, and in face of the fact, that almost count- 
the observations recorded may be expected to appear 1n the 
concluding ; 
Reverting now to the “Check Lists” above enumerated, we 
have in them almost a eomplete catalogue of the invertebrate 
fossils occurring in the North American beds from the dawn of 
