148
APTORNIS DEFOSSOROWEN.
- 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 | " |
Locality of type: Oamaru.
Habitat: South Island.
A nearly perfect skeleton in the Tring Museum, collected by Mr. W. S. Mitchel in limestone cave on Oreti River, Southland.
