191 



DINORNIS. 



THE skull is broad and much depressed, with a comparatively wide, 

 somewhat pointed and deflected beak. Breadth at the squamosals 

 twice the height at basi-temporal. It has a flattened frontal region, 

 and a wide median ridge on the upper surface of the praemaxillae. The 

 mandible is in the form of a narrow U, with the angle much inflected, no 

 distinct anticular process, and the symphysis moderately wide, narrowing 

 anteriorly, with a prominent and broad inferior ridge, widest in front. The 

 quadrate is elongated, with a very large pneumatic foramen. The sternum 

 is nearly as long as broad, very convex, with distinct coracoidal facets, 

 3 costal articulations, very small and reflected costal processes, the lateral 

 processes very broad and widely divergent, and a wide xiphisternal notch. 

 The pelvis is narrow with a high ilium, in which the inferior border of the 

 postacetabular portion is flat, and does not descend as a sharp ridge below 

 the level of the anterior postacetabular vertebrae. The pubis has a small 

 pectineal process; and the ventral aspect of the true and postacetabular 

 vertebrae is very broad and much flattened. 



The distal extremity of the tibio-tarsus is not inflected. A hallux is 

 present in some species. The tibio-tarsus and tarso-metatarsus are long and 

 slender, the length of the latter equalling and more often exceeding the 

 length of the femur, and also exceeding half the length of the tibio-tarsus. 

 The femur is comparatively long and slender, with a short neck, the head 

 rising but slightly and projecting only a small distance, the linear aspera in 

 the form of a long irregular line, the outer side of the distal extremity 

 moderately expanded, the popliteal depression small, deep, and sharply defined, 

 the profile of the inner cordyle semi-ovoid and narrow, and the interior 

 trochlear surface nearly flat. The phalangeals of the pes are long and 

 comparatively slender, the proximal surface of the terminal segments not 

 being trefoil-shaped. In the vertebral column the middle cervicals are long 

 and narrow, with the postzygapophyses directed much outwardly and separated 

 by a very deep channel, and the posterior face of the centrum low and 

 wide. The dorsals have short transverse processes and neural spine, the 

 anterior and middle ones (those with a haemal spine or carina) having a 

 large anterior pneumatic foramen between the nib-facet, the foramen being 

 triangular in shape. All the species of this genus are of comparatively large 

 size, and include the tallest members of the family. 



Type of the genus : Dinornis novaezealandiae (Owen). 

 Number of species : 7. 



