notes on a lower jaw of palorchestes azael. 221 



Notes on a Lower Jaw of Palorchestes Azael. 

 By Charles W. De Vis, B.A. 

 It may perhaps be allowed that a small accession to our scanty 

 knowledge of Australian palseosteology may be useful, even though 

 it merely tend to increase our acquaintance with known forms, 

 and define their taxonomic relations. By the kindness of one of 

 the Trustees of the Queensland Museum, W. H. Miskin, Esq., an 

 opportunity is given of describing the lower dentition and form 

 of jaw in a very young Palorchestes Azael, (Owen), and of noting 

 thereby some features of interest.. The fossil was obtained by Mr 

 Miskin from well-sinkers who met with it at a depth of 70 feet 

 near St. Ruth, on the Darling Downs. In the original condition 

 of the specimen the mandibles were displaced at the symphysis 

 forwards and upwards, and in this position reconnected by the 

 cementation of the mineralising agent, calcium carbonate. By 

 the more unlucky accident of pressure acting upon the anterior 

 third of the jaw transversely to its long axis, both rami have lost 

 their natural flexure. The left being certainly much straighter — 

 the right probably somewhat more strongly and abruptly curved 

 inwards at the symphysis, than in the normal condition. On clearing 

 away adhering matrix, the whole of the teeth, with the exception of 

 the left premolar, which has been carried away with a piece of the 

 bone, and the second molar of the same side, which is fractured, 

 were found in excellent preservation. The combined length of 

 the series d 4 m 1 m 2 , is exactly as in the portion of an adult 

 jaw figured by Professor Owen (Foss. Mant. Aust., PI. cvi., 

 fig. 1). The shallowness of the jaw below the growing molars, 

 characteristic of the young macropod, is a conspicuous feature 

 of the present fossil — its depth beneath the second molar 

 being little more than half that of the adult mandible, and 

 about two-thirds of the depth which it attains below the premolar. 

 The evidence derived from this deeping of the mandible from 

 behind forward, tending to show that Palorchestes was more 

 nearly allied to the kangaroo proper, than to the Protemnodontidse, 

 is of some weight, since, though not confirmed, it is not belied by 



