Page:Quarterly Journal of the Geological Society of London, vol. 29.djvu/591

1873.] parietal region (ib. 7) is smooth, transversely arched, and feebly impressed by the upper part of the crotaphyte fossa (figs. 1 & 2, ) opposite the middle of the occipital region.

The breadth of the cranium here is 1 inch 9 lines (0⋅045 m.); the length from the lateral occipital ridge to the hind margin of the orbit is 7$1⁄2$ lines (0⋅016 m.). If a transversely curved fracture of the upper part of the cranium had coincided with a coronal (fronto-parietal) harmonia, the fore and aft extent of the coalesced parietals at their median (sagittal) suture would be 5$1⁄2$ lines (0⋅012 m.). It is singular that a second fracture of the cranial roof should have commenced behind where the interfrontal suture terminated, and have extended forward to opposite the middle of the orbit; but this fracture soon quits the median line and inclines to the right; it is also complicated with a shorter posterior fracture starting from the transverse one simulating the coronal suture, but which curves unsymmetrically more forward on the left than on the right side.

The frontals, moderately convex transversely at their back part, become flat and then slightly concave in that direction as far as the fronto-nasal suture (Pl. XVI. fig. 4, ); this is not a fracture, or but partially so at its outer ends.

The length of the frontal part of the cranium is 2 inches (0⋅050 m.); the least breadth of the interorbital tract is nearly 6 lines (0⋅012 m.); the extent of the frontal suture is 9 lines (0⋅020 m.). The antorbital process of the lacrymal (fig. 2, ) is less mutilated on the left side of the fossil, which gives an appreciable idea of its size and shape.

Both fore and hind boundaries of the orbits (Pl. XVI. figs. 1, 2, 4, ) are partially broken away; but the antero-posterior diameter of those cavities seems to have been 1 inch 2 lines (0⋅030 m.); the vertical diameter is 1 inch 1 line (0⋅027 m.); they are of an oval form, with the. small end forward. There is no trace of a depression for a superorbital gland; the upper border of the eye-chamber is thin, not to say sharp.

In the basal portion of the upper mandible here preserved (figs. 1, 2, 4, ) there is no remaining trace of suture to mark the boundaries of the nasal, premaxillary, or maxillary bones.

An upper tract (fig. 4, ), flattened at its hind part, is defined by two obtuse linear risings converging from the ends of the fronto-nasal suture rapidly, then bending forward, broadening and converging gradually till lost in a median transverse convex ridge or tract, 2 lines (0⋅004 m.) broad at the anterior fracture; the breadth of this mid tract, where flat, at the beginning of the lines of minor convergence, is 4 lines (0⋅008 m.).

The sides of the base of the upper mandible slope outward as they descend to a longitudinal groove (figs. 1 & 2, g), with a slight curve concave downward, below which the upper jaw-bone descends vertically to the alveolar border.

The extent, lengthwise, of the upper beak-bone here preserved is, on the left side (fig. 2), from the end of the fronto-nasal suture, 1 inch 6 lines (0⋅037 m.), on the right side (fig. 1) 1 inch 1 line (0⋅027 m.); the vertical diameter of the base is 9 lines (0⋅020 m.),