382 PROFESSOR OWEN ON THE GBNTJS DINORNIS. 



met with a prompt and hearty response. The Trustees of the Australian Museum 

 directed the unique bird's bone to be moulded, and they forwarded to me a plaster cast. 



Mr. Kreift was so good as to have three photographs taken of the fossil : — one showing 

 the back view of the bone, three fifths the natural size ; the two others the front views 

 of the proximal and distal halves of the bone, of very nearly the natural size. 



With these evidences a satisfactory comparison can be made of the Australian fossil 

 with the femora of other large wingless birds, both recent and extinct. 



The bone is the right femur (Pis. LXII. & LXIII. fig. 1). It measures 11 inches 

 6 lines ; and there may be an inch more of this dimension lost by the abrasion to which 

 both ends have been subject. The middle thii'd of the shaft is entire, and shows its 

 natural form and surface; the breadth of this part is 2 inches 6 lines; the antero- 

 posterior thickness does not exceed 1 inch 7 lines (PI. LXIII. fig. 2). The extreme 

 breadth of the upper end is 5 inches 3 lines, that of the lower end is 5 inches ; but 

 these latter dimensions fall short, probably by half an inch, of those which the un- 

 abraded or entire femur would have yielded. 



Of the femora of Binornis I have selected that of Bin. elepJiaoitopus^, as nearest to 

 the present fossil in regard to length (13 inches) ; the breadth of the shaft is the same, 

 or, in the largest examples of B. elephanto]}us, exceeds only by 2 lines that of the 

 Australian femur. 



But the shaft of the bone in Bro7nomis is compressed from before backward ; its trans- 

 verse section is a narrow oval (PI. LXIII. fig. 2), while that of the Binornis is a fuller 

 and less regular oval (ib. fig. 3) from the greater proportion of fore-and-aft breadth of the 

 shaft. The back part of the shaft of Bromornis australis, besides being less convex 

 transversely, is devoid of the strong ridges and tuberosities which characterize that part 

 iu all the species of Binornis ; in this respect, as in the shape of the transverse section 

 of the femoral shaft, Brornornis resembles more that bone in the Emu [Bromaius ater). 

 The bifurcate anterior muscular (" intervastal ") ridge which characterizes the fore part 

 of the femoral shaft in Binornis elepliantopus (vol. vii. pi. 43. fig. 1), as in other species 

 of that genus, is not defined on that part of the femur of Bromornis (PL LXII. fig. 1). 

 The longitudinal ridge, descending from the pretrochanterian ridge to the ectocondylar 

 expansion, is traceable in the cast, but is less strongly marked than in Binornis. The 

 mutilation of the prominent parts at the proximal end of the femur begets a reticence 

 in drawing conclusions from apparent differences ; but some were evidently inherent in 

 the original when entire. The periphery of the head of the femur {d) is not constricted 

 so as give the appearance of a " neck," as it is in Binornis, 



The trochanterian part of the articular surface (c) is more horizontal, does not ascend 

 as it recedes from the head, in Bromornis. So far as the trochanter {f) is preserved in 

 the cast, and appears in the photographs, it does not rise above the level of the head [a) 

 of the femur, and seems not to have risen, when entire, so much above it as in Binornis ; 

 the lay of the trochanterian articular tract agrees with these indications of the remain- 

 ' Trans. Zool. Soc. vol. iv. (1856) p. 149, pi. 43. fig. 1. 



