ZEUQLODONTIDiB. 49 



Suborder ARCH^OCETI. 



Teeth differentiated into groups; nasals long. 



Family ZEUGLODONTID^. 



Dentition :— I. | C. i, Pm. and M. | The cheek-teeth (wood- 

 cut, fig. 10) have two distinct roots, and compressed pointed crowns 

 with denticulated cutting-edges. The cranium is elongated and 

 depressed ; the brain-cavity small ; the temporal fossae and the 

 sagittal crest are large ; the rostrum is long and largely composed 

 laterally of the premaxillee ; and the nasals are elongated, flat and 

 narrow. All the cervical vertebrae are free, and the lumbars 

 elongated. 



Genus ZEUGLODON, Owen\ 



All the known forms of the family may be provisionally referred 

 to this genus, which has been recorded from the Eocene of jN^orth 

 America, England, and Egypt. A tooth and caudal vertebra are 

 figured in the accompanying woodcut. 



Eig. 10. 



Zeuglodon ceioides. — A, molar tooth ; B, caudal vertebra : reduced. From the 

 Middle Eocene of North America. (After Lyell.) 



^ Lond. & Edin. PbiloB. Mag. vol. xiv. p. 302 (1839). The earlier name 

 Basilosaurus, Harlan, was withdrawn by its author. 



PART V. E 



