This catalogue is a classified list of all type specimens of the fossil plants, invertebrates, and vertebrates, including specimens mentioned in literature, in the collections of the Australian Museum, Sydney. Also included are plaster replicas (plastotypes) of important type specimens, and, when known, the institution in which the original specimen is stored is given. Genera and species are arranged in alphabetical order in their appropriate larger biological groups. The catalogue, containing almost 4,000 specimens, is complete to December, 1968. Type specimens are listed in alphabetical order according to genera and species in their various groups such as Foraminifera, Anthozoa, Pelecypoda, etc. Terminology of the types follows generally accepted usage-holotypes, paratypes, lectotypes, paralectotypes, syntypes, neotypes, and hypotypes. The latter may include any described specimen which does not fall into the preceding ,categories. When a new species has been based on a single specimen it has been listed as a holotype. Plaster replicas of type specimens in the collections of other institutions are included in this catalogue; to these the prefix "plasto" is added, and unless otherwise stated the registered numbers follow the letter "L".