PROFESSOR OWEN ON THE GENUS DINORNIS. 321 



in the smaller species, with the modifications of the ornithic type presented by most 

 Grallm and Gallincs {ib. fig. 4, Ciconia argala), but differs considerably from the cor- 

 responding part in the Ostrich {ib. fig. 2). In this largest of existing Struthionida the 

 epicnemial process (i) does not rise above the level of the proximal surface of the tibia, 

 but extends directly forwards, sends out a compressed and prominent procnemial 

 ridge {p) and a short thick obtuse process {k) from its outer side in place of the ecto- 

 cnemial ridge. In the Dinornis the posterior articular tuberosity (fig. 1, <) is divided 

 by a wider and deeper depression than in the Ostrich, from a smaller anterior prominence 

 to which a fibular ligament is attached (fig. 4, 1) : this depression in the Dinornis receives 

 the inner prominent division of the outer condyle of the femur ; the posterior tibial tube- 

 rosity rising into the space between that and the inner condyle, whilst the fore-part of 

 the outer condyle rests upon the inner side of the ascending tibial ridge : this occasions 

 a closer interlocking of the tibia and femur than in the Ostrich. The only difference in 

 the dimensions of the tibiae of the Dinornis giganteus from the North and Middle Islands 

 is a slight increase of the breadth of the distal end of the more recent and better-preserved 

 bones from the latter locality (see the 'Table of Admeasurements ') . I subjoin to the 

 figure of tlae well-preserved proximal end of one of these tibicc from the Middle Island, 

 figures of the same parts of the tibia in the Ostrich (fig. 2), Emeu (fig. 3), and Gigantic 

 Crane (fig. 4), all of the natural size. 



The tarso-metatarsal bones of the Dinornis giganteus from the Middle Island are more 

 generally and sensibly stronger in proportion to their length than the femora or tibiae, 

 compared with those from the North Island ; but I cannot venture to infer from this 

 evidence alone more than a stronger variety of the species : the degree of difference is 

 accurately given in the ' Table of Admeasurements.' 



A new species might with more reason be founded on the bones of the hind extremity 

 from the Middle Island, which agree in length with those of the Dinornis ingens, since 

 they surpass in thickness in a somewhat greater degree their homologues from the North 

 Island. This difference I have not only been able to appreciate with regard to the 

 femur and tibia on which the species D. ingens was founded*, but also with regard to 

 the tarso-metatarsal bones, having received one specimen from the North Island, trans- 

 mitted by Mr. Colenso, which presents intermediate dimensions between the tarso- 

 metatarsal bones referred to Dinornis giganteus and Dinornis struthoides, and having 

 compared it with three tarso-metatarsals of similar length in the collection of Mr. Percy 

 Earl. These differences will be appreciated by the ' Table of Comparative Dimensions '; 

 but I shall here notice these stronger bones from the Middle Island as belonging to 

 Dinornis ingens, var. robustus, until other parts of the skeleton, especially the skull, may 

 arrive, although the following differences of form are observable in the homologous 

 bones of the extremities from the two localities. 



* Loc. cit. pp. 247, 250. 

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