PROFESSOR OWEN ON THE GENUS DINORNIS. 247 



same proportion to the bone of sixteen inches in length, as this does to that of thirty- 

 five inches. The tibia of eight inches and two-thirds in length has its articular ex- 

 tremities as completely ossified and confluent with the shaft, and its proximal and fibular 

 ridges as strongly developed, as in the larger tibioe. The shape of its proximal articu- 

 lation (PI. XXVI. fig. 6.) differs more from that oi t4 than this does from that of < 2 ; 

 the tibial half is broader from behind forwards than transversely ; the anterior ridge at 

 the proximal end is nearer the middle of the bone than in 1 4, a fortiori, nearer than in 

 t 2 ; the inner side of the bone is more rounded or less angular, especially at the proxi- 

 mal half of the shaft ; the transverse diameter of the shaft is proportionally less than the 

 antero-posterior one ; the posterior notch between the distal condyles is deeper, and the 

 inner condyle (PI, XXV. fig. 6. g) is more compressed laterally, and is produced further 

 backwards. There is no tarso-metatarsal to match the tibia < 11 : this bone unequivo- 

 cally establishes a fourth species of cursorial bird, which, from the agreement of the bone 

 in its general characters with the tibiae of the larger species, most probably belonged to 

 the same genus, Dinornis, but did not surpass in size the Great Bustard {Otis tarda). 

 V I propose, therefore, to name the species to which it belonged, Dinornis otidiformis. 



The distal articular surface of the longest tibia, t 1, fits the proximal joint of the 

 longest tarso-metatarsal, m 1 . There is no tarso-metatarsal bone corresponding with 

 the tibia t 2. This bone agrees more closely in its proportions and configuration with 

 t 1 than with t 4 : from the latter it is evidently specifically distinct, but less clearly so 

 from the largest tibia. Yet the difference of size is sufficiently striking ; too great, 

 without other evidence, to justify the assumption that it depends on diff'erence of sex ; 

 and the mature characters of the shorter bone t 2 militate against the supposition of 

 a difference of age. At the proximal extremity the external ridge is relatively less 

 produced but thicker and stronger in t 2, and the internal condyle or boundary is 

 broader in t 2. In the next section we shall find that there are different-sized femora 

 with equally mature characters which correspond respectively with t 1 and t 2. These 

 considerations induce me to regard < 2 as indicative of a distinct species of Dinornis 

 which must have stood about nine feet in height, and may be provisionally called 

 y^ ' Dinornis ing ens.' 



The smallest tarso-metatarsal bones in the present collection, m 4, m 5, m 6, corre- 

 spond precisely with the tibiae < 3, M, i 8, < 9. The proportions of the shaft t 7 cor- 

 respond with those of the intermediate metatarsal, m 3. 



Femora. (PI. XXI. XXII. XXIII. XXIV.) 



The femur is remarkable for its great strength and the expansion of its extremities : 

 the smallest diameter of the shaft is one-seventh the length of the entire bone. The 

 trochanter a is unusually broad, thick and elevated ; the distal extremity is still more 

 remarkable for its great size, and especially for the breadth of its rotular concavity d. 



