6o SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 72 



be published in association with Lydekker. The arrangement is as 

 follows : 



Cetacea, 



Mystacoceti, Balcenoidea. 



Balcunidcu: Balsena, Neobalaena, Rhachianectes, Megaptera. 

 Balsenoptera. Extinct Genera : Cetotherium, Herpetocetus. 

 ArcltcFoceti. 



Zcnglodontidce: Zeuglodon. 

 Odontoceti, Delphinoidea. 

 Physeteridco. 



Physeterinee : Physeter, Cogia. Extinct : Physeterula, Eucetus, 



Physetodon, Scaldicetus, Physodon, Hoplocetus. 

 Ziphiinse : Hyperoodon, Ziphius, Mesoplodon, Berardius. 

 Extinct : Choneziphius. 

 SqualodontidcE: Squalodon. 



Platanistidce : Platanista, Inia, Pontoporia. Extinct: Palseopon- 

 toporia (Pontistes), Champsodelphis, Schizodelphis, Pris- 

 codelphinus, Lophocetus, Ixacanthus, Rhabdosteus, 

 Agabelus. 

 Delphinid(P. 



Group A. Monodon, Delphinapterus, Phocaena, Neomeris, 



Cephalorhynchus, Orcella, Orca, Pseudorca, 



Globicephalus, Grampus, Feresia, Lageno- 



rhynchus. 



Group B. Delphinus, Tursiops, Prodelphinus, Steno, Sotalia. 



Max Weber (Die Saugethiere, 1904) agrees closely with the con- 

 ception of Flower and Lydekker. One of the greatest differences is 

 that a special family, RhachianectidcB is established for Rhachionectes 

 and also a family Delphinaptcridce for Delphinapterus and Monodon. 



Abel has made special researches on the fossil Cetacea, and he has 

 tried to determine their positions in relation to the recent forms. 

 Besides what he has said on the subject in his special monographs, 

 he has more or less completely set forth his ideas in the papers : Die 

 Stammesgeschichte der Meeressaugetiere ; Meereskunde, Sammlung 

 volkstiimlicher Vortrage, 1907 ; Grundziige der Palaentologie der 

 Wirbeltiere, 1912; and Die vorzeitlichen Saugetiere, 1914. He has 

 not given a;ny general synopsis except in the following genealogical 

 tree, published in his work Die Vorfahren der Bartenwale, 19 14 



