| OCR Text |
Show 112 MR. 0. W. ANDREWS ON REMAINS OP .EPYORNIS [Feb. 6, (Plate X I V . figs. 3 & 4), both unfortunately incomplete at the upper end. The dimensions of these bones are:- Length Width of distal end Width of shaft at narrowest point Circumference of shaft at nar rowest point Shortest antero-posterior dia meter M. titan. cm. 800 170 7-5 20-7 4-5 M. maximus. M. hildebrandti. cm. 64-0 135 15-5 cm. 48-5 8-2 11-0 The shaft is slightly curved, the inner border being concave. The flattening of the lower part of the anterior face, characteristic of the genus, is here more strongly marked than in the other species, and extends rather farther up the shaft. This flat surface is bounded on either side by a ridge, that on the inner side being the stronger ; these sharply separate the anterior from the lateral surfaces, which with the posterior form a continuous curve from side to side, rather flattened behind, especially towards the lower end of the bone. The lateral surfaces are also flattened and rough in the same region. A linea aspera runs obliquely across the upper part of the anterior face from the procnemial crest to the inner border, which it reaches about 32 cm. above the lower end of the bone. In the other species of ASpyornis of which the tibio-tarsus is known, as well as in Dinornis, this ridge takes a more longitudinal course and only reaches the inner border a httle above the condyles. Immediately above the latter is a short ridge running up the face of the bone and having at its lower end a rugose tubercle. Between this ridge and the inner border is the groove for the extensor tendons of the digits, deep at its lower end and dying away as it is traced upwards. As in the other species there is no ossified extensor bridge. About 2-5 cm. above the outer condyle is a large foramen for the passage of a blood-vessel into the bone. The condyles have the form characteristic of the genus. The inner is the larger and projects more forward. The intercondylar surface is only slightly depressed and, though faintly convex from side to side, does not form a distinct ridge between the condyles such as is figured by Burckhardt in AS. hildebrandti. The lateral surfaces of the condyles have very deep pits for the insertion of ligaments, that in the outer being 2-5 cm. deep. Behind these pits are large rugose tuberosities. The surface for the fibula closely resembles that of AS. maximus. The wall of the bone is very hard and compact, and is about |
