PROFESSOE OWEN ON THE FOSSIL MAMMALS OF AUSTEALIA. 



521 



The head of the same skeleton was sent some years ago to Sydney. The shepherd who 

 discovered the head is here still, and it was he who showed me the place. When 1 can 

 get time and men in that direction I will dig it out and then forward it by degrees to you.' 



" Since I received this account," proceeds Dr. Bennett, " I have seen Mr. W. B. Tooth, 

 the owner of the station, and he informed me that he has a large blade-bone, and that 

 when he visits the station and has the men at leisure, he will gradually dig out the 

 skeleton as perfect as possible and forward it to me. Mr. T. left on the 15th of this 

 month for the station. I suggested to him to preserve every bone however small, which 

 he has promised to do. On my receiving only a few at a time I will immediately transmit 

 them to you, as I expect it will take some time to excavate the whole skeleton, as men 

 cannot be spared at all times from a large sheep station." 



I have long (perhaps too long) deferred entering upon the work of the present com 

 munication, hoping to complete the materials for the entire reconstruction of the Dipro- 

 todon. But the quick lapse of time, its inevitable effect on mind and body, and the 

 venial impatience of the possessors of nondescript bones of the great Marsupial, combine 

 to put an end to delay, and I proceed, therefore, to the description of the parts of this 

 extinct animal at present at my command. 



§ 2. Skull. — It is probable that the specimen in the British Museum (Plate XXXV. 

 figs. 1, 2, 3), purchased at the sale of a series of Australian Fossils sent to London from 

 Sydney by a Mr. Boyd, and stated to have been obtained from the bed of a creek at 

 Gowrie, near Drayton, Darling Downs, Queensland*, may be the " head " referred to in 

 the letter above cited. 



The chief dimensions of this skull are given in the 'Table of Admeasurements' of parts 

 of the skeleton of Diprotodon, p. 573. 



The skull shows the general marsupial character of that part in its degree of depres- 

 sion, or flattening from above downward, in the small proportion devoted to receive the 

 brain, and in the large proportion given to the olfactory chamber and precranial air- 

 sinuses. 



The occipital region (Plate XXXV. fig. 1, 3, fig. 3), instead of being vertical, as in 

 Macropus (ib. fig. 5) and most existing Marsupials, slopes forward from the terminal con- 

 dyles at an angle of 45° with the basicranial axis. 



The basioccipital (ib. fig. 3, i) forms by a thick border convex vertically, slightly 

 concave transversely, the lower part of the rim of the foramen magnum (ib. o) an inch 

 in extent, separating in the same degree the lower ends of the occipital condyles (ib. 2, 2). 

 These ends may be contributed by the basioccipital element, but the sutures between it 

 and the exoccipitals are obliterated. 



* " All the above fossil remains are from King's Creek, Darling Downs, being the same locality whence the 

 entire skuU of the Biprotodon was obtained some years ago." — W. S. Macleat, in ' Repoi-t on Donations to 

 the Australian Museum during August, 1857.' See also " Owen, On Nototherium," in Proceedings of the Geo- 

 logical Society of London, March 1858, p. 158. 



4 B 2 



