150 
TERTIARY VERTEBRATA OF TKE FAYOM. 
PalaBomastodon beadnelli, Andrews. 
[Plates XII.-XVI. ; text-tigs. 50 A, 51.] 
1901. P aloiomastodon beadnelli, (t W. Andrews, Tageblatt des V. Internationalen Zoologen-Con- 
gresses Berlin, No. G, p. 4 (Verhandlnn gen, p. .528, 1902) ; 
Zoologist, [4] vol. V. p. 319 ; Geol. Mag. [4] vol. viii. 
pp. 401-403, Hg. 1 (mandible). 
1903. ,, ,, C. W. Andrews, Phil. Trans, vol. 19G b, pp. 110-113, figs. 10-1.3 
(skull and mandible). 
1904. „ ,, C. Andrews, Geol. Mag. [5] vol. i. pp. 112-115, fig. 2 (skull). 
Type Specimen. — Left ramus of mandible with pm. 4 (broken) and m. 1-3 (PI. XV. 
figs. 1, 1 a); 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-postevior 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 s[)ecies 
is uncertain. The mental foramen opens almost immediately beneath the anterior end 
of pm. 3, and therefore some distance behind the symphysis. 
Form. A Loc. — Fluvio-mariue beds (Upper Eocene) : north of Birket-el-Qurun. 
C. 10014 . Iniperfoct left ramus of mandible with pm. 4 and m. 1-3. The typo specimen noticed 
in ‘Tageblatt des V. luternalionalen Zoologon-Congresses,’ No. G, 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 arc : — 
Total length of specimen 61 
l)e])th of ramus in middle of diastema 9*(> 
,, „ immediately in front of pm. 15 l()-5 
„ „ „ beneath pm. 4 12 
