4l8 CLASSIFICATION OF THE CETACEA 



C Grey Whales {Eschrichtiidae = Rhachianectidae) . Post-glacial - 

 Recent. Dorsal fin absent, 2-4 grooves, short baleen. 



I Californian Grey Whale [Eschrichtius gibbosus (Erxleb.) = Rhachia- 

 nectes (Eschrichtius) glaiicus Cope], 41 ft. N. Pacific. 



D Rorquals (Balaenopteridae) Upper Miocene - Recent. Dorsal fin, 

 40-100 grooves, short baleen. 



1 Blue Whale [Balaenoptera miisculus (L.) ], 80 ft. Universal. 



2 Fin Whale [Balaenoptera physalus (L.) ], 68 ft. Univei'sal. 



3 Sei Whale [Balaenoptera borealis (Lesson) ], 46 ft. Universal. 



4 Brjde's Whale [Balaenoptera brydei (Olsen) = B. edeni Anderson], 

 42 ft. Tropics and sub-tropics. 



5 Little Piked Whale (Lesser Rorqual, or Minke Whale) [Balaenoptera 

 acutorostrata Lacép.], 30 ft. Universal, but rare in tropics. 



6 Hurtipback Whale [Megaptera novae-angliae (Borowski) = Megaptera 

 nodosa (Bonnnat.)], 45 ft. Universal. 



3 Odontoceti (Toothed whales) 



Upper Eocene - Recent. Recent types have uniform teeth. Nostrils on 

 top of skull. Skull of recent types asymmetrical. Arterial grooves run 

 behind transverse processes of caudal vertebrae. 



A SquALODONTiDAE. Upper Eocene to Lower Pliocene. Teeth still 

 differentiated. Molars with jagged edges. Includes the Agorophiidae 

 (Upper Eocene). Squalodontidae proper only known from Upper 

 Oligocene - Lower Pliocene. 



B Sperm Whales (Physeteridae) . Lower Miocene - Recent. Older types 

 with well-developed teeth on both jaws. After Upper Miocene strong 

 reduction of teeth in upper jaw. Recent types have only rudimentary 

 teeth in upper jaw. Cuttlefish eaters. 



1 Sperm Whale [Physeter macrocephalus L.], S 51 ft. ? 38 ft. Universal. 



2 Pigmy Sperm Whale [Kogia breviceps (Blainv.)], 13 ft. Universal. 



C Beaked Whales {^iphiidae). Lower Miocene - Recent. Older types 

 with well-developed teeth in both jaws. After Upper Miocene strong 

 reduction of teeth. Most recent types have only 1-2 visible teeth in 

 lower jaw. Pointed beak. Two longitudinal grooves on throat. Cuttle- 

 fish eaters. 



1 Bottlenose Whale [Hyperoodon ampidlatus (Forster) ], 30 ft. N.Atlan- 

 tic, and Hyperoodon planifrons Forster, Antarctic. 



2 Cuvier^s Whale [,^iphius caviroslris Cuv.], 27 ft. Universal. 



