PROFESSOR OWEN ON THE GENUS DINORNIS. 151 



IS relatively nearer the proximal end of the bone : the two tuberosities below this are 

 closer together : the two sides (fig. 3, s&t) of the fibular groove (fig. 3, r) are at a more 

 open angle, and the groove is less deep in Dinornis elephantopus, the outer side, t, 

 being less produced, as compared with Din. robustus. The antero-posterior breadth 

 of the outer and inner condyles is equal in Din. elephantopus, as it is in Din. robustus ; 

 but in Din. a-assus 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 Din. ele- 

 phantopus. 



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 

 in the ' Zoological Transactions,' vol. iii. p. 247. 



Tibia of Dinornis elephantopus. 

 Dimensions of the Tibia in 



Length 



Transverse breadth of proximal end . . 



Fore-and-aft breadth of ditto 



Least circumference of shaft 



Transverse breadth of distal end 



The characters of the upper end of the tibia of Dinornis elephantopus (PL XLIII. 

 fig. .5) closely accord with those of the Din. robustus, 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 Din. robustus. The almost 

 flat articular surface for the inner condyle of the femur is somewhat less in its shorter 

 diameter : the epicnemial ridge, k, is less extended transversely : the ectocnemial 

 ridge, e, curves more strongly outward : but there are individual varieties in all these 

 characters in the tibiae before me. All, however, differ in the earlier subsidence of the 

 ridge continued downward from the procnemial plate, p, which ridge is continued in 

 Dinornis robustus uninterruptedly to that above the inner division of the distal trochlea. 

 The space between the ecto- and pro-cnemial plates in Dinornis crassus is rela- 

 tively greater than in either of the above larger species : the ridge continued from 

 the procnemial plate is interrupted as in Din. elephantopus. The concave fore part of 

 the tibia between the ectocnemial, e, and procnemial, p, ridges is impressed by irregular 

 vascular grooves. The fibular ridge is interrupted by a smooth tract, in or near which 



' The extremes of size in a series of several bones are here given. 



z2 



