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, 7) are at a more 
open angle, and the groove is less deep in Dinornis elephantopus, the outer side, ¢, 
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. 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 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 
D. robustus. D. elephantopus. D. crassus. 
feet. in. lines. feet. in. lines. feet. in. lines. 
2» 0) 70 1 7 6! 
Wenethi.).1-). saciesysits =e «islue ne 2S 3 { jh gttleg io Telling 
3 OWT a5 
Transverse breadth of proximal end .. Of = 1G { Ona ett 0 \ OQ GB 2 
2 Oo 4 6} 
Fore-and-aft breadth of ditto........ Omred OF9 { Os \ OF 43S 6 
Least circumference of shaft ........ OSG nO ON iy wb) On 47 10 
4 2 
Transverse breadth of distal end...... 0 4 4 { auaig \ Oe sy 08 
The characters of the upper end of the tibia of Dinornis elephantopus (Pl. XLII. 
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 tibiz 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. 
72 
