Pig. 9. 



;fl ._'*- M| 



Side View op the Head op the Timsa or Nile Crocodile 



(Crocodilus niloticus). 



X Fourth lower tooth. 



(Photographed from a specimen in the Museum.) 



Fig. 10. 



«& 



Side View op the Head op the N. American Alligator 



(A lligator mississippiensis) . 



(Photographed from a specimen in the Museum.) 



{To face page 10. 



