1900.] .FOSSIL MARSUPIAL FROM TASMANIA. 785 



and on the other hand agreeing with the majority of recent ones, 

 in which it is variable and only feebly developed l . 



The coronoid process is that of the right side (fig. 8). It is a 

 remarkably thin plate, in comparison with the general solidity of 

 the other bones, with the anterior and upper margin but little 

 thickened. In comparison with that of other marsupials it is of 

 considerable breadth ; there is no concavity on the lower half of 

 the outer surface such as is present in most forms. The form of 

 the posterior curved margin, where it is passing backwards and 

 downwards towards the condyle, may be taken as indicating that 

 the latter was placed fairly high up as regards the angle of the 

 jaw. 



Limb-bones. 



These are represented by a fairly complete left and a broken 

 right femur ; a left tibia broken distally, and a right tibia also 

 broken ; a left fibula broken distally and a right more perfect one. 

 No part of the anterior limb or of the foot is preserved. 



The Femur (text-fig. 1, and figs. 10, 11, PI. L.).— The left 

 femur (figs. 10, 11, PI. L.) is entire except for the upper end 

 of the trochanter, which evidently rose slightly beyond the head. 

 Its total length is 107 mm., and when compared with the cor- 

 responding bone of a Trichosurus, which is of about equal 

 length, it is at once seen to be remarkable on account of its 

 massiveness. The shaft is straight without any anterior curve, 

 and the posterior surface is flattened. A line passing along 

 the long axis practically cuts through the tip of the great 

 trochanter, the head being turned considerably inwards. The 

 lesser trochanter is characterized by the strong development of 

 the tuberosity at its upper end ; while the ridge, which is con- 

 tinued downwards from the great trochanter, has a marked 

 tuberosity at its lower end similar to that which is present in 

 Phascolomys. At its ventral distal extremity the shaft swells 

 out, the lateral surface of the outer side being turned, so that it 

 becomes visible in ventral view as in the femurs of Phascolomys 

 and Phaseolarctos. There is also a distinct depression beneath the 

 inner condyle, which is present but not so strongly developed in 

 Phaseolarctos. 



The condyles are of interest because, whilst in marsupials it is 

 characteristic to find the outer larger (in Macropodidse and 

 Phalangeridie notably so) than the inner, the reverse condition 

 obtains here, and the inner one is slightly larger than the outer — 

 a point of structure in which the fossil apparently differs from all 

 other Marsupialia. 



On the anterior face at the condylar end there is a broad surface 

 with only a slight development of groove, the latter being less 

 marked even than in Phalangers and Dasyures, in which there is 

 a broad, distinctly concave surface with distinct margins. What 



1 H. F. Osborne, " Mesozoic Marsupialia," Journ. Acad. Nat. Sci. Phila- 

 delphia, vol. ix. 2, 1888, p. 262, 



