250 PROFESSOR OWEN ON THE GENUS DINORNIS. 
but is of very small size; it leads, however, to a more expanded cavity, and may pro- 
bably have given passage to one air-cell, penetrating for a little way into the neck of 
the femur. At the distal end of the bone (fig. 6) the articular production separating the 
tibial from the fibular articular surface on the outer condyle is more ridge-like, and is 
less produced backward, than in Dinornis didiformis’. 
§ 9. Lidia. 
The tibia of Dinornis parvus (front view in figure of skeleton, Pl. LI., oblique back 
view, ib. Pl. LVIII.) shows the chief generic characters of the bone in the great relative 
breadth and height of the rotular or epicnemial plate, in the wide concavity between 
this plate and the proximal articular surfaces, in having the same direction and 
relative extent of the ridge for the attachment of the fibula, and in the completion by an 
oblique bridge of bone of the canal transmitting the tendon of the ‘extensor tibialis 
anticus’*. 
The large, slightly concave, articular surface for the inner condyle of the femur is 
divided from the small convex surface for the inner side of the intercondyle by a well- 
marked smooth wide groove. The prominence closing the outer end of that groove is 
less developed than in Dinornis gravis* and most of the larger species. The procnemial 
ridge subsides within 3 inches of its summit, and is not continued, as in D. gravis*, to 
the groove for the extensor tendon. The ectocnemial process has a similar extent. The 
fibular ridge subsides, as usual, at the entry of the medullarterial canal, beyond which 
a rough narrow tract, not rising above the surface of the bone, indicates the continua- 
tion of the ligamentous attachment of the slender distal half of the fibula to the tibia. 
On the opposite side of this bone commences, at 3 inches from the distal end, a well- 
marked, rough, slightly depressed surface, gradually widening to 7 lines across, where 
it terminates + inch above the distal border of the inner (‘ tibial’) condyle. 
The anterior part of the distal articular surface of the tibia has not the mid 
rising interrupting the transverse concavity as in Dinornis gravis’. For the rest, the 
distal articular and other characters of the leg-bone closely conform to the dinornithic 
type. 
I may remark that in comparison with the Bustard (Otis tarda), to which Dinornis 
parvus is little superior in size, the tibia is thicker relatively to its length, and, with 
other osseous characters of the legs, is indicative of the more powerful actions and 
varied uses to which the Moas of New Zealand applied their feet. 
Both proximal and distal epiphyses are as thoroughly confluent with the diaphysis 
in the present small species as in the tibia of the largest Moas. 
1 Compare fig. 6, Pl. LVI. of the present Memoir with fig. 3, pL xxxv. Trans. Zool. Soc. vol. iii. 
* See these and other characters defined and figured, of the natural size, in Trans. Zool. Soc. vol. iii. 1843, 
pls. xxy., XXvi. 5 Trans. Zool. Soc. vol. viii. pl. lix. fig. 3, d. 
* Thid, vol. viii. pl. lix. fig. 1, g. * Tom. cit. pl. lix. fig. 2, u. 
