CLASSIFICATION OF THE CETACEA 



1 Archaeoceti 



Lower Eocene - Upper Oligocene. Dissimilar teeth. Nostrils not 



situated on top of head (with one exception). Skull symmetrical. 



Arterial grooves run in front of transverse processes of caudal vertebrae. 



A Protocetidae. Lower Eocene to Middle Eocene. Primitive types. 

 6h ft. -29 ft. Protocetus, Pappocetus, Eocetus. 



B DoRUDONTiDAE. Upper Eocene - Upper Oligocene. Non-serpentine 

 shape. Up to 17 ft. Dorudon, ^ygorhiza, Phococetiis, Kekenodon. 



C Basilosauridae. Middle Eocene - Upper Oligocene. Serpentine 

 shape. 38 ft.-65 ft. Prozeuglodon, Basilosaurus, Platyosphys. 



D Patriocetidae. Upper Oligocene. Nostrils have migrated back- 

 wards. Patriocetus. 



2 Mystacoceti (Baleen whales; Whalebone whales) 



Middle Oligocene - Recent. Whalebone, Nostrils on top of head. Skull 

 symmetrical. Arterial grooves run in front of transverse processes of 

 caudal vertebrae. 



A Cetotherudae. Middle Oligocene ~ LoAver Pliocene. Primitive 

 types. 8 ft. -32 ft. Aglaocetus, Cophocetus, Mesocetus, Alixocetus, Ceto- 

 Iherium, Parietobalaena. 



B Right Whales {Balaenidae). Lower Miocene - Recent. Dorsal fin 

 absent, no grooves, long whalebone. 



1 Greenland Right Whale [Balaena mysticetus L.]. 51 ft. Arctic Ocean. 



2 Biscayan Right Whale (North Atlantic Right Whale; southern type 

 = Southern Right Whale) [Eubalaena glacialis Bonnat. or E. 

 aiistralis Desm.], 48 ft. Distributed throughout the oceans but not 

 in tropical seas. 



3 Pigmy Right Whale [Caperea {Neobalaena) marginata (Gray) ], 19 ft. 

 Antarctic Ocean. 



417 CG 



