Geological Society. 73 



2. Adult male and female, from San Cristoval, Soloman Group 

 of Islands, Dec. 1855. Presented by John Macgillivray, Esq. and 

 F. M. Rayner, Esq. in 1856. 



GEOLOGICAL SOCIETY. 



March 10, 1858.— Prof. Phillips, President, in the Chair. 



u Notes on some Outline-drawings and Photographs of the Skull 

 of Zygomaturus trilobus, Macleay, from Australia." By Prof. Owen, 

 F.R.S., F.G.S. 



About a month since Prof. Owen received from Sir R. Murchison 

 seven photographs, three of which are stereoscopic, of perhaps the 

 most extraordinary Mammalian fossil yet discovered in Australia. 



These photographs, with a brief printed notice of their subject by 

 William Sharp Macleay, Esq., F.L.S., and some MS. notes by J. D. 

 Macdonald, M.D., R.N., had been transmitted to Sir R. Murchison 

 by His Excellency Governor Sir W. Denison, from Sydney, New 

 South Wales ; and by desire of Sir Roderick the Professor brought 

 the subject under the notice of the Geological Society of London, to 

 whom Sir Roderick desires to present the photographs on the part 

 of His Excellency Sir W. Denison. 



Professor Owen had some weeks previously received from George 

 Bennett, Esq., F.L.S., of Sydney, outlines of the same fossil skull, 

 made by him on the reception of the specimen by the authorities of 

 the Australian Museum at that town ; and the Professor had penned 

 notes of his comparisons of these sketches before receiving the 

 photographs and descriptions of the fossil skull from Sir R. I. Mur- 

 chison. 



This unique and extraordinary skull of a probably extinct Mam- 

 mal, together with other bones, but without its lower jaw, were 

 found at King's Creek, Darling Downs, — the same locality whence 

 the entire skull and other remains of the Diprotodon have been ob- 

 tained. 



Mr. Macleay has described the fossil under notice as belonging 

 to a marsupial animal, probably as large as an Ox, bearing a near 

 approach to, but differing generically from, Diprotodon. He has 

 named it Zygomaturus trilobus. The skull has transversely ridged 

 molars, and a long process descending from the zygomatic arch, as 

 in the Megatherium and Diprotodon, and exhibits an extraordinary 

 width of the zygomatic arches. The skull at its broadest part, 

 across the zygomata, is 15 inches wide, and is 18 inches long. In 

 Diprotodon the skull is about 3 feet long by 1 foot 8 inches broad : 

 so that while the latter must have had a face somewhat like that of 

 the Kangaroo, the Zygomaturus more resembled the Wombat in the 

 face and head. 



Prof. Owen stated that, from the evidences afforded by the photo- 

 graphs, he finds the dentition of this upper jaw to consist of three 

 incisors and five molars on each side, of which the first appears to be 

 a premolar and the rest true molars, i. <?., i. — , c.*^-, i?.— , m- 4 — ? 

 agreeing, in this formula, with Macropus and Diprotodon. The mo- 



