PROFESSOR OWEN ON THE GENUS DINORNIS. 249 



thicker and stronger bone, and yet has more signs of immaturity. We in like manner 

 associate together / 7,/ 8, / 17, as not varying beyond a line from the length of eight 

 inches. 



In the first four femora,/ 1,/ 2,/ 3,/ 12, enumerated in the table, there is a more 

 regular gradation of size. The left femur, / 12, is eleven inches, and the shaft of a 

 right lemur,/ 4, so precisely corresponds in circumference and other proportions as to 

 leave no doubt as to their similarity in length, and render it highly probable that they 

 belonged to the same bird. The femora / 2 and / 3 were thirteen inches in length ; 

 and the shaft/ 1 indicates a femur of at least sixteen inches in length. 



In an Ostrich the circumference of the femur, of the tibia, and of the metatarsus is 

 respectively five inches three lines, four inches three lines, and three inches seven hues. 

 In an Emeu the circumference of the same bones is respectively three inches seven lines, 

 three inches four lines, and three inches. 



From these analogies we may conclude that the shaft of the femur / I, with a cir- 

 cumference of seven inches and three lines, may have belonged to a Dinornis with the 

 largest tibia whose circumference is six inches six lines, and with the tarso-metatarsal 

 bone whose circumference is five inches six lines, the proportionate thicknesses of 

 these bones to each other being intermediate in their degrees to those presented by the 

 same bones in the Ostrich and the Emeu. It must be remembered that the relative 

 length of the femur and metatarsus is very different in the Dinornis from that in existing 

 Struthionida, the Apteryx excepted; but, according to the above collocation of the 

 femur, tibia and tarso-metatarsus of the largest Dinornis, the tarso-metatarsus exceeds 

 the femur in length by 2^ inches in this species, which I have named Dinornis giganteus. 

 The femur/ 2 presents a similar correspondence with the tibia t 2 ; but its excess of 

 length over the tarso-metatarsus m 3 renders it very improbable that they could belong 

 to the same species, especially when the difference in their circumference is added, 

 that of the femur being six inches one line, that of the metatarsus four inches three 

 lines ; besides, the distal articulation of the tibia t 2 is obviously too large for the arti- 

 culation of the metatarsus m 3. The femur / 12 offers the required correspondence 

 with the metatarsus m 3 of the Dinornis struthoides, which exceeds the length of that 

 femur by one inch, and is consequently but a little shorter in proportion than in the 

 largest species. 



The tarso-metatarsus is proportionally still shorter in the third species {Dinornis didi- 

 formis), to which I refer the femora / 7, /8,/ 17, the tibis t3, M, t5,t8,t9, HO, and 

 the tarso-metatarsal bones m 4, m 5, m 6. The tibia, according to this aUocation, being, 

 like that of the gigantic Dinornis, httle more than twice the length of the femur, we 

 may with great probability associate the shaft of the tibia, which, when restored, gives 

 a length of twenty-five inches, with the femur of the Dinornis struthoides measuring 

 eleven inches in length. 



The proportions of the three principal bones of the leg in the Ostrich, the Emeu, the 



