Oporornis, ii. [279]

Opossum, extinct in European Miocene, i. 121

Opossums, ii. [248]

Opsariichthys, ii. [452]

Opsiphanes, ii. [472]

Orang-utan, ii. [171]

Orca, ii. [209]

Orcaella, ii. [209]

Orchesticus, ii. [99]

Orchilus, ii. [101]