158 Dr. C. W. Andrews — JVotes on Egijptian Eocene Mammals. 



wall of the cranium. It bears a large post - tj'rapanic and also 

 a large post-glenoid process, the two approaching one another, 

 though not meeting, beneath the auditory meatus. The glenoid 

 surface is very broad from side to side, but narrow and deeply 

 concave from before backwards. The orbits are not marked off 

 in any way from the temporal fossae ; there are large antorbital 

 foramina. The pre-nasal buttress of bone, running from the pre- 

 maxilla3 to the nasals and helping to support the front of the great 

 horns, seems to be formed mainly by the premaxillee. The pterygoids 

 form extremely large palatine plates, and the palate is very deeply 

 concave from side to side, particularly in front. 



In the mandible the ascending ramus is high, and the coronoid 

 process rises considerably above the transversely elongated condyle. 



The teeth (Plate VI, Figs. 1-3). The dental formula is \.%] c.\; 

 pm. J ; m. ;)-• The tooth series is closed, and in the mandible at 

 least the crowns all wear to a common level, and there is no clear 

 line of distinction between the premolars, canines, and incisors ; 

 but, on the other hand, in both upper and lower jaws the difference 

 between the premolars and molars is most striking. The molars 

 are especially remarkable for the height of their crown, particularly 

 on the outer side. Each molar (see Figs. 1 and 3) consists of two 

 columns {pc. and ac.) flattened antero - posteriorly, and with the 

 posterior face slightly concave from side to side. The enamel - 

 covered portion of the outer side of these elements is very much 

 higher than on the inner side. These main columns are united 

 on the inner side of the tooth only, where also are developed the 

 smaller accessory crests marked x and y in the figures. In wear 

 (see m. 2 of Fig. 1) these accessory elements, together with the 

 inner ends of the main columns, unite to form an inner wall, 

 which, except just at first, is not covered with enamel (Fig. 1). 

 The premolars present a totally different appearance. In them there 

 is an outer wall covered with enamel and consisting of two, or more 

 probably three, united elements. There are two inner cusps, the 

 anterior of which soon becomes united with the ectoloph, as in very 

 worn teeth the posterior one does also; anteriorly the element 

 marked x in the molar is present. The peculiar arrangement of the 

 roots in the cheek teeth and the probable homologies of their cusps 

 will be described later. It seems probable that we have here an 

 extreme modification with great hypselodonty of one of the types 

 occurring among the earlier Amblypoda. The canines and two 

 posterior incisors are simple columnar teeth with a cingulum on the 

 inner side, wearing to a flat surface continuous with that of the 

 cheek teeth. The anterior pair of incisors are not well known to me, 

 but they appear to have been separated by a considerable interval in 

 the middle line, and to have possessed curved and pointed crowns 

 with a shelf-like development of the cingulum posteriorly. 



The lower molars are at first bilophodont, each consisting of a pair 

 of obliquely transverse crests, the anterior faces of which are slightly 

 concave from side to side and not covered by enamel. The outer 

 angle of the posterior crest is united by a ridge with the inner 



