The skull from Muskham, in the valley of the Trent, a side view of which is given in Plate XI., like the animal bones with which it was associated, is stained of a dark-brown colour. The whole of those parts of the cranial bones which bound the cranial cavity are well preserved; but the facial bones, with the exception of a small portion of the nasals, are broken away, so as to expose the whole of the under-surface of the base of the skull.

The considerable development of the frontal sinuses and of the different ridges and processes of the skull, shows it to be that of an adult, and the same characters lead me to believe that it belonged to a male. Otherwise it is small enough for a female, as its extreme length does not exceed 7·2 in., its extreme breadth 5·4 in., and its horizontal circumference 20½ inches.

The skull has a very peculiar form. If a line drawn from the glabella to the superior curved line of the occiput be made horizontal, the highest point of the longitudinal median contour of the skull will be seen to be situated about the middle of the length of the sagittal suture, and from this point the contour shelves rapidly downwards, to the brow on the one hand, and to the centre of the space between the apex of the lambdoidal suture and the occipital protuberance on the other. This last is the most prominent portion of the back part of the skull, the median contour below it bending forwards to the occipital protuberance, which is a very strong, projecting, triangular process.