280 
ELEMENTS OF GEOLOGY. 
Fig. 224. Fig. 225. 
Zeuglodon cetoides, Owen. Basilosaurus, Harlan. 
Molar tooth, natural size. Vertebra, reduced. 
confirmed by Dr. Wyman and Dr. R. W. Gibbes. That it 
was an extinct mammal of the whale tribe has since been 
placed beyond all doubt by discovery of the entire skull of 
another fossil species of the same family, having the double 
occipital condyles only met with in mammals, and the con¬ 
voluted tympan ic bones which are characteristic of cetaceans.. 
