Prof. Owen on the Dinornis elephantopus. 



171 



nearer to the head of the bone than in the Dinornis rohustus ; 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 the Dinornis 

 elephantopus. The intermuscular ridge continued from the tro- 

 chanterian one seems to bifurcate sooner in the Dinornis elephantopus. 

 The depression behind the trochanterian ridge is less deep in the 

 Dinornis elephantopus. The oblique rotular channel is relatively as 

 wide and deep as in the Dinornis rohustus, but the inner boundary 

 formed by the fore part of the inner condyle is shorter. 



At the back part of the shaft the medullo-arterial foramen is 

 relatively nearer the proximal end of the bone ; the two tuberosities 

 below this are closer together. The two sides of the fibular groove 

 are at a more open angle, and the groove is less deep in the Dinornis 

 elephantopus, the outer side being less produced. 



The antero-posterior breadth of the outer and inner condyles is 

 equal in the Dinornis elejihantopus as in the Dinornis rohustus ; but 

 in the Dinornis crassus that dimension of the outer condyle exceeds 

 the same dimension in the inner one, and the fibular groove is more 

 open or shallow than in the Dinornis elephantojms. 



The generic modifications of the femur are, however, very closely 

 preserved in each species, being strictly of the type ascribed to the 

 genus Dinornis in my original memoir, Zool. Trans, vol. iii. p. 247. 



Dimensions of the tibia in D. robustus. 



Ft. In. Lines, 



Length 2 



Transverse breadth of proximal end 7 



Fore-and-aft breadth of do 4 



Least circumference of shaft 6 



Transverse breadth of distal end... 4 



D. crassus. 

 Ft. In. Lines. 



1 7 6* 

 1 6 6 



6 2 



3 6 



4 10 

 3 3 



The characters of the upper end of the tibia of the Dinornis 

 elephantopus closely accord with those of the Diriornis rohustus, 

 and the difference of size, as exemplified in the foregoing table, is so 

 slight, that had this extremity only of the bone reached me, I should 

 most probably have referred it to the Dinornis rohustus. The 

 almost flat articular surface for the inner condyle of the femur is 

 somewhat less in its shorter diameter ; the epicnemial ridge is less 

 extended transversely ; the ectocnemial ridge curves more strongly 

 outwards ; but there are individual varieties in all these characters in 

 the tibiae before me. All the tibiae, however, differ in the earlier sub- 

 sidence of the ridge continued downwards from the procnemial plate, 

 which ridge is continued in Dinot'nis rohustus uninterrupted by that 

 above the inner division of the distal trochlea. The space between 

 the ecto- and pro-cnemial plates in the Dinornis crassus is relatively 

 greater than in either of the above larger species ; the ridge con- 



* The e.vtremes of size in a series of several bones are here given. 



