402 Dr. C. W. Andreivs — Extinct Egyptian Vertebrates. 



myself in Lower Miocene at Moghara, to the north-west of the 

 present locality, and it seems probable that this mandible may have 

 belonged to an ancestor of that well-known Miocene species. 



The mandibular ramus (Fig. 1) is long and relatively narrow 

 from above downwards, and is very slightly decurved anteriorly. 

 It is chiefly remarkable for the elongation of the edentulous region 

 in front of the cheek-teeth ; in this region the alveolar border forms 

 a sharp edge without trace of tooth sockets. The symphysis com- 

 mences about 12 cm. in front of the anterior premolar, but its length 

 cannot be determined, as the anterior portion of the jaw is broken 

 away. Judging, however, by the large size of the central canal 

 at the broken end, it seems probable that the symphysis was 

 considerably elongated, though possibly not to the same extent as 

 in M. angustidens. The base of an alveolus for a tusk (Fig. 1, i) is 

 preserved on the broken end. 



The coronoid process rises from the outer surface opposite the 

 posterior third of the last molar; but its upper part is broken 

 away, as also are the condyle and the angle. The cheek-teeth are 

 distinctly proboscidian, and the molars are very similar to the 

 anterior molars of some Mastodons. There were originally five 

 teeth in situ, but the anterior one (pm. 3) has fallen out of its 

 socket, the form of which indicates that this tooth had two roots, 

 a smaller anterior and a larger posterior ; probably the crown was 

 triangular in outline. The next tooth (pm. 4) is much broken ; it 

 seems to have consisted of a high anterior ridge, a median trans- 

 verse crest, only traces of which remain, and a small posterior 

 ridge now much worn. The next tooth (m. 1) is likewise 

 trilophodont, the hinder crest being much the smallest. It is 

 much worn and considerably broken on the inner side. The suc- 

 ceeding molars are in an excellent state of preservation. Both are 

 trilophodont, but in the last the hinder ridge (talon) is considerably 

 larger than in m. 2. Each transverse ridge is evidently composed 

 of two tubercles, and is connected with the ridge behind by a very 

 slightly developed longitudinal prominence. Small tubercles occur 

 at the inner ends of the transverse valleys in m. 3. The outer 

 ends of the ridges are far more worn than the inner, which stand 

 up considerably above the rest of the tooth-crown. There is 

 a regular increase in the degree of wear from m. 3 to m. 1. It 

 seemed just possible that the tooth here described as m. 1 might 

 be the last milk-molar, but its state of wear compared with that 

 of the other teeth, and the absence of any trace of a premolar germ 

 in the jaw beneath it or of a molar behind those now described, 

 prove that the interpretation here adopted is the correct one. 



It will be seen that this genus differs from Mastodon in the greater 

 simplicity of m. 3, and in the fact that two premolars and three 

 molars are in use at once. I propose the generic name Palceomastodon 

 for this form, the name of the species being P. Beadnelli after 

 Mr. H. J. L. Beadnell, of the Egyptian Geological Survey, to whom 

 the discovery of these fossils is mainly due and by whom the survey 

 of the Faytim area has been carried out. 



