Since the communication of the paper “On Thylacoleo,” in the “Philosophical Transactions” for 1871, further explorations of the caves and breccia-fissures in Wellington Valley, New South Wales, have been made, by a grant for that purpose from the Legislature of the Colony, and carried out by E. B. Ramsay, Esq., F. L. S., Curator of the Museum of Natural History, Sydney. The present paper treats of the fossils contributing to the further restoration of the great carnivorous Marsupial (
Thylacoleo carnifex
, Ow.). They exemplify the entire dentition
in situ
of the upper and lower jaws of a nature individual: the bones of the fore-limb, of which those of the antibrachium and the ungual phalanges are described, are compared with those of other Marsupials, and of placental, especially feline,
Carnivora
. An entire lower jaw with the articular condyles adds to the grounds for determination of the habits and affinities of the extinct Marsupial. Figures of these fossils of the natural size accompany the paper.