150 TERTIAET VEETEBEATA OF THE FAYtM. 



Palaeomastodon beadnelli, Andrews. 



[Plates XII.-XVI.; text-iigs. 50 A, 51.J 



1901. Falceomastodon beadnelli, C. W. Andrews, Tageblatt des V. Internationalen Zoologen-Con- 



gresses Berlin, No. 6, p. 4 (Verhandlungen, p. 528, 1902) ; 

 Zoologist, [4] vol. V. p. 319; Geol. Mag. [4] vol. viii. 

 pp. 401-403, fig. 1 (mandible). 



1903. „ „ C. W. Andrews, Phil. Trans, vol. 196 B, pp. 110-113, figs. 10-13 



(skull and mandible). 



1904. „ „ C. W. Andrews, Geol. Mag. [5] vol. i. pp. 112-115, fig. 2 (skull). 



T^pe Specimen. — Left ramus of mandible with pm. 4 (broken) and m. 1-3 (PI. XV. 

 figs. 1, 1a); Geological Museum, Cairo. 



The type species and the largest yet known. The length of the molar and premolar 

 series in the lower jaw is 28 cm. The molars are distinguished by the comparatively 

 small development of the accessory and intermediate cusps and the antero-posterior com- 

 pression of the main cusps, the consequence of these peculiarities being that the teeth 

 are more distinctly lophodont than in the other species, with the exception of the small 

 P. minor. The last lower molar has no talon beyond a slight ridge of the cingulum, 

 which is almost as strongly developed in m.2. The molars also differ from those of 

 P. wintoni and P. minor in being wider in proportion to their length ; in this respect 

 they resemble the molars of P. parvus. The elongation of the mandibular ramus 

 between the anterior end of the cheek-teeth and the symphysis also distinguishes 

 P. beadnelli from P. wintoni and P. minor, in which the posterior end of the symphysis 

 is very little in front of the anterior premolar {pm. 3) : in P. beadnelli the interval is 

 about 12 cm. The degree to which the symphysis is prolonged in the present species 

 is uncertain. The mental foramen opens almost immediately beneath the anterior end 

 oipm. 3, and therefore some distance behind the symphysis. 



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



C. 10014. Imperfect left ramus of mandible with pm. 4 and m. 1-3. The type specimen noticed 

 in ' Tageblatt des V. Internationalen Zoologen-Congresses,' No. 6, p. 4 (Berlin 1901) • 

 also described and figured in Geol. Mag. [4] vol. viii. (1901) p. 401 ; also PI. XV. 

 figs. 1, 1 A. The dimensions (in centimetres) of this specimen are : — 



Total length of specimen 61 



Depth of ramus in middle of diastema g.g 



,, ,, immediately in front of pm. 3 10-5 



„ „ „ beneath pm. 4 12 



