_Aptornis otidiformis_ Owen, ibidem p. 347 (1848).
This is the North Island form, and I must refer my readers to Owen's description, only remarking that Mr. Hamilton, Trans. N.Z. Inst. XXIV, p. 179, says the vertebrae assigned by Owen to _Cnemiornis_ all belong to _Aptornis_.
Locality of type tibia: Poverty Bay, North Island, New Zealand; collected by Rev. Wm. Williams in 1842. { 148}
_Aptornis defossor_ Owen, Trans. Zool. Soc. VII, pp. 353 to 366, pls. 40-44 (1871).
The skull differs from that of _A. otidiformis_ by the vertical surface of the descending part of the occiput being less deeply concave, the occipital foramen relatively smaller. The hind part of the base of the alisphenoid is more produced and tuberous outside the end of the hyoid process of the paroccipital in _A. defossor_.
The chief other differences in size, according to Owen, are as follows:--
_A. defossor_. _A. otidiformis_. _Skull._ Length 7.2 inches. 6.2 inches. Breadth across paroccipitals 3.3 " 2.9 " Breadth across postfrontals 3.2 " 2.10 " Breadth across temporal fossae 2.3 " 1.1 " Breadth of base of upper mandible 1.6 " 1.3 " Breadth of middle of upper mandible 1.4 " 1.1 " Breadth of fore end of upper mandible 0.7 " 0.6 " Length of premaxillary 5.0 " 4.3 "
_Femur._ Length 7.6 " 6.2 " Breadth of proximal end 2.2 " 1.9 " Breadth of distal end 2.2 " 1.9 " Circumference of middle of shaft 2.9 " 2.3 "
_Tibia._ Length 10.3 " 8.9 " Breadth of proximal end 2.3 " 1.9 " Breadth of distal end 1.10 " 1.3 " Circumference of middle of shaft 2.6 " 1.11 "
_Metatarsus._ Length 4.4 " 3.10 " Breadth of proximal end 1.8 " 1.5 " Breadth of distal end 1.9 " 1.6 " Breadth of middle of shaft 1.6 " 1.4 "
A nearly perfect skeleton in the Tring Museum, collected by Mr. W. S. Mitchel in limestone cave on Oreti River, Southland.
Differs from _Fulica_ by the much more curved shape of the skull, the deeply marked glandular impressions over the eyes, and the great pneumaticity of the frontal bones.
_Fulica chathamensis_ H. O. Forbes, Nature, vol. XLVI p. 252 (1892).
_Fulica newtoni_ H. O. Forbes, l.c. (non Milne-Edwards).
_Palaeolimnas newtoni_ H. O. Forbes, Ibis 1893, p. 544.
_Palaeolimnas chathamensis_ Milne Edwards, Ann. Sci. Nat. (VIII) 2, 1896 p. 130.