226 REPORT — 1844. 



the jaw. This part more decidedly manifests the marsupial character by its 

 inward inflection and by the broad flattened surface whicli the under part of the 

 jaw there presents ; this surface forms a right angle with the outer surface of 

 the ramus, the lines of union being rounded off'; the outer surface, which is 

 entire to the base of the coronoid process, is slightly concave. The Elephants, 

 Mastodons, and Tapiroid Pachyderms present the opposite or convex form of 

 the outward surface of the jaw ; the Dinotherium comes nearest, amongst the 

 Pachyderms, to the character of the angle and ba^e of the ascending ramus 

 of the jaw manifested in the present fossil ; which however, in the greater 

 degree of inflection and flattening of the angle, more closely adheres to the 

 marsupial type. The alveolar ridge is continued backwards, for the extent of 

 two inches, in the form of a flattened platform of bone, forming an angle at 

 its inner and posterior extremity. The thin base of the coronoid process 

 extends along the outer border of this platform, and the entry of the dental 

 canal is situated near the posterior end of the base of the coronoid. The 

 condyloid process and the back part of the jaw are broken away ; a great part 

 of the thick ridge formed by the inwardly inflected angle of the jaw has also 

 suffered fracture ; but about one inch of the middle part of this characteristic 

 structure is entire. The preserved fangs of the last molar show it to have 

 been as large as would comport with the proportions of the molars in the pre- 

 ceding specimen. 



The following fossils not only extend our knowledge of the dentition of 

 the under jaw of the Diprotodon, but also of the range of the species over 

 the continent of Australia ; they were discovered by Mr. Patrick Mayne 

 a few feet below the surface, during the operations of sinking a well, near 

 Mount Macedon, in the district of Melbourne, and are noticed by Mr. Augus- 

 tus F. A. Greeve, in the 'Port Phillip Patriot' of February 5th, 1844. He 

 specifies the incisor as that " of a large animal, most probably a gigantic 

 Wombat," and after an account of the molar teeth, thus concludes : — " But I 

 feel assured that it is a new and most interesting genus ; the discovery, in fact, 

 of the gliriform type of the Pachydermata, the connecting link between the 

 family which comprehends the Beaver and Rabbit with that of the Elephant, 

 the Horse and the Hippopotamus ! " 



Mr. Greeve appears to have been unacquainted with my descriptions of the 

 Australian fossils in Major Mitchell's work, or he would probably have recog- 

 nised the similarity between his specimens and those which had led me to 

 establish a new genus and to indicate its aflRnities, as manifesting the gliri- 

 form type of the marsupial order on a gigantic scale. A series of the speci- 

 mens discovered by Mr. Mayne having been transmitted to me by my friend 

 Dr. Hobson, I was enabled to identify them with the Diprotodon of the caves 

 of Wellington Valley and of the plains near Moreton Bay, and it was with 

 peculiar satisfaction that I afterwards perused the concurrent testimony of 

 Mr. Greeve as to their indications of a distinct genus, and of the resemblance 

 of the incisor to that of the Wombat, which had struck me so forcibly at 

 the commencement of my investigation in 1837 of the fossil remains of the 

 Diprotodon. The fossils from Mount Macedon are in a very different con- 

 dition from those discovered in the bed of the Condamine river; they are 

 not impregnated with mineral matter, but are extremely light and fragile, 

 having lost all their animal matter, and consequently adhering strongly to the 

 tongue ; they are in almost the same state as the remains of the Megatherioid 

 quadrupeds from the recent deposits forming the Pampas of Buenos Ayres. 



The teeth are principally from the same under jaw, of which an outline 

 was transmitted to me by Dr. Hobson, the original having crumbled to dust 

 on exposure to the air. The first specimen consists of the under part of the 



