352 



expansion and straight direction, that of the larger species, and the more 

 perfect condition of the smaller pelvis proves that the extremity of this 

 bone projects freely backwards, as in the Apteryx and Emeu. 



1562. A mutilated pelvis of a smaller species of Dinornis, probably Dinornis 

 didiformis, Owen. It is less entire than the preceding specimen, but 

 manifests characters which prove it to belong to a distinct species of 

 Dinornis, and apparently to an older bird, since the second sacral rib on 

 the left side is anchylosed to the vertebral interspace. This anchylosis 

 sufficiently demonstrates that the present pelvis is not of a younger bird 

 than the preceding pelvis, No. 1561 ; and.besides the difference of size, there 

 are the following differences of configuration : — In the present pelvis the 

 second and third sacral ribs arise nearer the lower surface of the bodies 

 of the vertebrae, a character by which it approximates the largest pelvis, 

 No. 1 558, from which it differs in having the bodies of these vertebrae 

 relatively less broad and flat. The extent occupied by the four posterior 

 orifices forming the interspaces of the lower transverse processes of the 

 third to the seventh sacral vertebrae inclusive, is three lines greater in the 

 present pelvis than in the one next in the order of size, No. 1561. The 

 bodies of the four vertebrae without lower transverse processes are flatter 

 below in the present than in No. 1561. The vacuity at the sides of these 

 vertebrae, into which the posterior aperture of the acetabulum opens, is 

 relatively much smaller in the present than in No. 1561 ; but the two 

 transverse processes of the twelfth and thirteenth vertebrae which abut 

 against the posterior part of the acetabulum are absolutely much thicker 

 in the present specimen. Such differences are not manifested in the 

 pelvis of individuals of the same species in other birds : they are asso- 

 ciated in the present instances with minor differences in the shape of the 

 acetabulum, especially of its posterior and inferior border, and in the 

 relative breadth of the bodies of the posterior sacral vertebrae ; the latter, 

 however, might be a sexual difference. Seventeen of the sacral vertebrae 

 are preserved in the present specimen, and the expanded spinous plate of 

 the posterior ones is more perfectly preserved than in the preceding pel- 

 vis, No. 1561. 



