354 



The chief generic characters of the tibia of the Dinornis are, the broad 

 and wide concavity anterior to the proximal articular surface, the great 

 breadth of the ascending wall of bone for the implantation of the rotular 

 or extensor tendon, and, at the distal end, the slight anterior production 

 of the lateral ridges of the trochlea. All these characters are very 

 strikingly distinctive when the tibia of the Dinornis is compared with 

 that of the Ostrich ; the difference is less, though well-marked, in rela- 

 tion to the Emeu or Apteryx. The tibia of the Dinornis differs from 

 that of all known existing Struthious birds in the presence of the canal 

 above the distal trochlea on the anterior and inner side of the bone, 

 formed by the oblicme osseous bridge across the extensor tendon. The 

 affinity of the Dinornis to the Bustard and other Gralloe, and to the 

 GallirKB, is indicated by this structure. The inner condyle or division 

 of the distal trochlea is relatively more produced backwards than in the 

 Strut hionidcE and Grallce generally. The anterior crista at the head of 

 the bone is less developed than usual. The longitudinal ridge for the 

 fibula on the proximal half of the bone is well-marked; but the fibula 

 has not been anchylosed to it. The orifice of the canal for the medul- 

 lary artery is close to the termination of the fibular ridge. Notwithstand- 

 ing the great length of this tibia, it is relatively thicker than in the 

 Ostrich and other known long-legged birds. 



] 56/. The left tarso-metatarsal bone of the Dinornis giganteus, apparently of 

 the same individual bird as the preceding specimen. It measures eighteen 

 inches and a half in length, five inches and a half in circumference at the 

 middle of the shaft, and five inches in breadth across the distal end. The 

 tarso-metatarsal bone of the Dinornis consists of the tarsal and of three 

 primitively distinct metatarsals blended together, and forming, as usual, 

 a single bone, divided at the distal extremity into three trochlear arti- 

 culations, for the three toes. The proximal articulation presents two 

 concavities, the inner one the deepest, and the dividing ridge is slightly 

 produced upwards at its anterior termination into a conical obtuse pro- 

 cess. The margins of the proximal end of the present bone have been 

 broken and worn away, but enough remains to show, that as in Nos. 

 1574 and 1585, there are two short and thick longitudinal ridges at the 



