MEGALOHTEAX MINOE. 97 



Form,. & Loc. — Fluvio-marine beds (Upper Eocene) : north of Birket-el-Qurun. 

 Upper Dentition (PI. VII. fig. 1). — Except in their smaller size the upper molars 

 of this species closely resemble those of M. eoccenus, the only notable diiFerences being 

 the absence of the small accessory styles of the outer face of m. 1 and m. 2, and the fact 

 that the main outer cusps form slight projections on the ectoloph. The premolars, on 

 the other hand, difier more considerably from those of the larger species, the chief point 

 of difference being that they are more simple. Thus in pm. 4 there is a fairly well- 

 developed postero-internal cusp, but it is smaller than in the corresponding tooth of 

 M. eoccenus, and the tooth is less quadrate in outline. In^m. B the postero-internal 

 cusp is practically absent and its position is occupied by a shelf-like projection ; the 

 same is the case with the other premolars. In pm. 1 the antero-internal cusp also is 

 much smaller than in M. eoccenus, and approximates in form to the canine of that 

 species. In fact, each of the premolar teeth of the present species resembles the next 

 tooth in front of it in M. eoccenus, rather than the corresponding tooth. 



It can be seen that the posterior border of the zygomatic process of the maxilla is 

 about opposite the hinder lobe of m. 3. 



Lower Dentition (PL VII. figs. 2, 3). — The collection at Cairo includes portions of 

 the right and left rami of a mandible which probably belongs to this species and 

 possibly to the same individual as the type specimen. The portion of the left ramus 

 preserved contains the two anterior incisors (fig. 3, i. 1, i. 2), the third and fourth 

 premolars, and the first and second molars. The right half (figs. 2, 2 a) includes 

 the three posterior premolars and the molars. Unfortunately, the two rami do not 

 join, some fragments of bone being wanting, and in the left ramus the alveolar 

 border is incomplete between the second incisor and the third premolar, so that the 

 exact dental formula cannot be determined. The incisors (fig. 3), of which, probably, 

 only two pairs were present, are of somewhat peculiar form, and in the present 

 specimen they are considerably worn. The crowns are broad and spatuJate, and 

 in the case of the anterior one (^. 1) somewhat flattened on the anterior face. 

 The wear-surface in each forms a narrow band along the whole of their upper 

 edge. They show no trace of the peculiar pectinate form seen in the incisors of 

 the recent Hyraces, but it is by no means impossible that this may have existed in the 

 unworn tooth. 



The cheek-teeth (fig, 2), so far as known, form a closed series. The molars consist 

 of two crescents : the postero-internal end of the anterior crescent terminates in a 

 cusp (ai.) which is joined posteriorly with another small cusp, which partly closes 

 the opening of the posterior crescent. This cusp is the metastylid {msd.}, and is 

 strongly developed in all the teeth from the third premolar back. In pm. 2 it is not 

 present. The third molar has a small talon (t.) giving a crescentic surface in wear. 

 The cingulum is fairly well developed on the outer side of the last premolar and 

 in the molars. 



