Geological Society. 73 



2. Adult male and female, from San Cristoval, Solomau 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. 



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

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

 F.ll.S., F.G.S. 



About a month since Prof. Owen received from SirR. Murchison 

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

 most extraordinary Mammalian fossil yet discovered in Australia. 



These photographs, with a brief j)rinted notice of their subject by 

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

 Macdonald, AI.D., R.N., had been transmitted to SirR. 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 tlie Professor had jjcnned 

 notes of his comj)arisons of these sketches before receiving the 

 photograjjlis and descri})tions of the fossil skull from Sir R. 1. Mur- 

 chison. 



This unique and extraordinary skull of a ])robabIy 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 skuU and other remains of the Dijjrotodon have been ob- 

 tained. 



Mr. Macleay has described the fossil under notice as belonging 

 to a marsupial animal, proi)ably as large as an Ox, bearing a near 

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

 named it Zyrjomaturus trilobus. The skull has transversely ridged 

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

 in the Megather'nmi 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 IS inches long. In 

 Diprotodon the skull is about 3 feet long by 1 foot S 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- 

 grajjhs, he finds the dentition of this ui)per jaw to consist of three 

 incisors and five molars on tach side, of which the first a])pears to be 



1 1 .1 ^ .. 1 • • 3—3 0—0 1 — I 4 — 1 . 



a premolar and the rest true molars, t. e., i. — , c. — , /;. — , m. — , 

 agreeing, in this formula, with Macrepus and Dipi-otodon. The mo- 



