130 



AUSTRALIAN ANCESTRY OF THE CROWNED PIGEON OF 



close agreement with the fossil. In section this end of the shaft is 

 in Gallus an oval flattened posteriorly — in Goura and the fossil 

 triangular and very similar, the chief difference being that in the 

 extinct bird the outer edge of the bone on this aspect is like the 

 inner one compressed and sharp instead of being obtusely rounded 

 as it appears in the recent pigeon ; further this sharp edge is con- 

 tinued proximal to the outer edge of the ectocondylar articulating 

 surface and by its lateral dilatation produces with the calcaneal pro- 

 cess a concavity corresponding to but shallower than that of the 

 inner side of the bone, in this feature it departs from Goura and 

 Approaches Gallus. 



The distal expansion is more rapidly formed and, relative to 

 the breadth of the shaft, is much greater in the pigeon than hi the 

 fowl, in both these respects there is an exact parallelism between 

 Goura and the fossil bones. The articulating surface for the first 

 metatarsal is placed much higher on the metatarse in Goura than in 

 Gallus, and on the inner edge of the shaft : not as in the rasorial on 

 the palmar aspect of the bone external to that edge ; in the elevated 

 position of the scar and in its extent, which causes a distinct pro- 

 jection upon the outline of the bone on its inner edge, the extinct 

 bird agrees with Goura, but inasmuch as the scar is on the hinder 

 surface of the shaft, indicating a more directly backward direction 

 of the hind toe, it shows in this an approximation to the poultry 

 birds. The inner trochlea is distinctly higher than the outer in 

 Gallus, slightly higher in the fossil and on the same level with it in 

 Goura : the outer trochlea is lower in the fossil than in Goura, show- 

 ing by so much a greater dej arture from Gallus in this respect. 

 In the form of this pulley all three birds fairly agree, its rotular 

 surface in the fossil is distinctly grooved as it is in Gallus but not in 

 Goura, the same may be said ( f the inner trochlea. The shaft of 

 the fossil is at this end compressed and thus resembles Gallus 

 rather than Goura. 



On the whole, affinity with Goura, indicated by the shortness 

 of the calcaneal process, sudden attenuation of the inner edge of the 

 bone at its proximal end, elevation of the hind toe, rapid expansion 

 of the distal end and subequal descent of the "lateral trochleas, is 

 strongly predominant, but it is qualified by the many less importan* 



