]50 PROFESSOR OWEN ON THE GENUS DINORNIS. 



Feraur of Dinornis elephantopus. 



Commencing with the femur, I shall premise the following Table of admeasurements 

 of that bone in the three above-named species of Dinornis. 

 Dimensions of the Femur in 



D. robustus. D. elephantopus. D. erassus. 



in. liues. in. lines. in. lines. 



Length 1^ 2 13 11 10 



Transverse breadth of proximal end 6 5 10 4 5 



Fore-and-aft breadth of ditto 5 4 5 3 9 



Transverse breadth of distal end 6 5 11 4 7 



Fore-and-aft breadth of ditto 4 3 3 9 3 5 



Circumference (least) of shaft 7 10 7 9 6 



The above comparative dimensions bring out the characteristic proportions of the 

 femur of Dinornis elephantopus (PI. XLIII. fig. 1), as shown by its greater thickness 

 and strength. Compared with the femur of Din. robustus, this character is remark- 

 ably exemplified in the articular extremities (PI. XLIII. figs. 2 & 3). Had these 

 parts alone of Din. elephantopus been preserved and submitted to me, I should have 

 scarcely ventured upon a conclusion as to their specific distinction from D. giganteus, 

 or its representative on the Middle Island, D. robustus, the correspondence of con- 

 figuration being so close and the difference of size so slight. 



The articular surface is continued from the head upon the upper part of the neck 

 (PI. XLIII. fig. 2), expanding as it approaches the great trochanter, along the summit of 

 which it is terminated by a ridge. In both species the surface for attachment of the 

 ligamentum teres is formed, as it were, by a portion of the inner and back part of the 

 hemispheric head, having been cut off obliquely with a slight excavation. The corre- 

 sponding ligamentous surface in the head of the femur of Din. erassus is relatively 

 smaller, less depressed and less defined. The upper and fore part of the trochanter is 

 less produced relatively to the breadth of the supra-trochanterian articular surface in 

 Dinornis elephantopus. In this species the subcircular rough surface for the attachment 

 of the iliacus internus muscle (fig. 1 , i) is relatively nearer to the head of the bone than 

 in Dinornis robustus -. the rugged and thick fore part of the great trochanter descends 

 lower upon the shaft ; indeed the shortness of the entire bone seems to depend chiefly 

 on the shaft being relatively shorter in Din. elephantopus than in D. giganteus or robustus. 

 The intermuscular ridge continued from the trochanterian one down the fore part of the 

 shaft bifurcates sooner in Din. elephantopus. The depression behind the trochanterian 

 ridge is less deep in Din. elephantopus. 



The oblique rotular channel is relatively as wide and deep as in Din. robustus, but 

 the inner boundary formed by the fore part of the inner condyle is shorter in Din. 

 elephantopus. At the back part of the shaft of the femur the medullo-arterial foramen 



