and of a Bird from the London Clay. 205 



sal suture runs transversely across the cranium parallel with the anterior boundary 

 of the orbits. 



The lacrymal bone reaches a very little way upon the face. The external angle 

 of the base of the nasal bone, which is of considerable breadth, joins the lacry- 

 mal, and separates the superior maxillary from the frontal bone. 



The anterior margin of the malar bone encroaches a little way upon the face at 

 the anterior boundary of the orbit. 



The external aperture of the sub-orbital canal is situated about three-fourths of 

 an inch from the anterior boundary of the orbit. 



The under surface of the palatal processes of the maxillary bones is rugose, as 

 in the Peccari ; the portion of the skull, including the intermaxillary bones and 

 the incisive teeth, is unluckily broken off and lost. 



That the eye was full and large, is indicated by the size of the optic foramen and 

 the capacity of the orbit, the vertical diameter of which equals one inch. 



The upper part of the cranium, anterior to the sagittal suture, is slightly convex 

 from side to side, its longitudinal contour is nearly straight. The face gradually 

 becomes narrower anteriorly ; it is slightly concave at the sides. 



The general form of the skull was probably intermediate in character between 

 that of the Hog and the Hyrax. The large size of the eye must have given to the 

 physiognomy of the living animal a resemblance to that of the Hare and other 

 timid Rodentia. 



Without intending to imply that the present small extinct Pachyderm was more 

 closely allied to the Hyrax than as being a member of the same order, and similar 

 in size, I propose to call the new genus which it unquestionably indicates, Hyra- 

 cotherium, with the specific name leporinum. 



The indications which the present fossil has yielded of the generic characters 

 and form of the Hyracotherium are the more interesting on account of the absence 

 of similar information regarding the equally rare extinct Eocene genus Charopota- 

 mus, with which it is most closely allied. 



The resemblance of the molar division of the dental system in the Hyracothe- 

 rium and ChcBropotamus is sufficiently close to warrant the conclusion, that their 

 canines and incisors, if not precisely similar, would differ only in form and pro- 

 portion. Hence we may venture to remove, analogically, some of the uncertainty 

 which still attaches itself to the dental characters of the Charopotamus. 



" Avoit il en haut une canine comme en has?" asks Cuvier, in his account of 

 the fragments of jaws on which he founded the genus. Their presence in the pre- 

 sent fossil warrants an affirmative reply being given to this question. With respect 

 to the incisor teeth, these, together with the ossa intermaxillaria, are wanting in 

 the present specimen ; and they have not yet been found in any of the fragments 



