PROFESSOR OWEN ON THE GENUS DINORNIS. 155 



attachment of the rudimental back toe, there is no trace in the metatarse of Dinornis 

 elephantopus. 



The form of the articular pulleys for the three toes is shown in PI. XLIV. fig. 3. 



Toe-phalanges of Dinornis elephantopus. 



The bones of the foot I shall compare with those oi Dinornis robustus\ to which they 

 make the nearest approach in size. 



Equalling, or nearly equalling, the phalanges of that bird in breadth and thickness, 

 they differ chiefly in shortness, but in a less degree than the metatarsi differ. 



These proportional characters of the species are best given and easiest appreciated in 

 the plates (compare the above-cited Plate I. with PI. XLIV.). A few minor differences, 

 however, may be noticed : the outer portion of the proximal end of the first phalanx of 

 the inner toe, i, ii., is broader in proportion to its fore-and-aft diameter in Dinornis 

 elephantopus. The inner portion of the proximal end of the first phalanx of the outer 

 toe, 1, IV., presents the like diflFerence : the general form of that articular surface, fig. 3, 

 II. & IV., is less triangular and more oval in both the specified phalanges of Dmorm's 

 elephantopus ; the under side being indented as usual in the proximal phalanges of the 

 inner and outer toes. 



The modifications in the other phalanges, besides those of size and proportion, are 

 not greater or other than might be expected in different species of the same genus. 



Of the very remarkable species o{ Dinornis based upon the powerfully developed limbs, 

 the bones of which are described in the foregoing pages, Mr. Mantell's collection 

 includes five right and eight left femora, three right and four left tibiae, nine right and 

 fourteen left fibulae, three right and eight left metatarsi ; together with a considerable 

 collection of toe-bones, from which, probably, other entire feet might be reconstructed 

 in addition to the one of the left foot here exhibited, figured in Plate XLIV.- 



There are also two femora and two metatarsi of an immature bird, apparently, by 

 their proportions, from one individual of Dinornis elephantopus, PI. XLV. fig. 1 ; to 

 which may also belong the proximal end of a tibia, wanting the articular epiphysis. 



The femora, as in other birds, retain the two articular ends, which are simply rougher 

 than in the adult, having been covered by a thicker cartilage ; but are not developed 

 upon distinct osseous pieces, as in land mammals. 



The proximal epiphysis is wanting in both the immature metatarsi, the left of which 

 is figured in PI. XLV. fig. 1, so that they exhibit the separate expanded ends of the three 

 constituent bones, as shown in fig. 1, a ; which bones terminate in the three prominent 

 trochlese below. The length of the femur of this young bird is 1 1 inches, that of the meta- 

 tarse 7-5 inches. They already present the characteristic robustness of the adult bird. 

 ' See Trans. Zool. Soc. vol. iv. pi. 1. 



^ The bones of the entire right foot of apparently the same individual bird have been determined and restored 

 since the above was written. 



