108 
TBETIAllY VERTEBRATA OF THE FATOM. 
M. 8892. I’histor cast of the above specimen. Made in the British Museuin. 
C. 8016. Immature left til)ia, imperfect at ends. 
C. 9221. Immature right tilua, rather .^mailer than last, imperfect at ends. 
C. 8334. Left astragalus, the ])roximal articulation of which agrees with the distal articulation of 
the tibia just described. This bone is figured (text-fig. 59) and is very similar to 
that described above (p. 149) and figured (text-fig. 52). It is chiefly rematd<.able 
for file prominence of the knob forming its postero-internal angle. The dimensions 
(in centimetres) are : — 
AVddtli of tibial surface, including facet for internal malleolus . 5‘8 
„ calcaneal surfaces 5'G 
„ navicular surface 5 
M. 9237. Plaster cast of the above specimen. Made in the British Museum. 
C. 8636. Left astragalus, similar to last. 
M. 8406. Left astragalus, similar to last. 
PalaBomastodon minor, Andrews. 
[Plate XIV. figs. 1, 1 a; and text-fig. 50 D.] 
1904. P alcEomastodon minor, C. W. Andrews, Geol. Mag. [5] vol. i. p. 115. 
Type Specimen . — Portion of the right ramus of the mandible of a young individual 
(PI. XIV. figs. I, 1 a); British Museum. 
This species is not only much smaller than P. headnelli and P. wintoni, but differs 
in the structure of its molars, particularly of m. 3. This tooth is long in proportion 
to its width ; it consists of three complete transverse main crests and a small talon- 
like fourth ridge consisting of several small cusps, 'fhe anterior crest is composed 
of two large cusps, the outer of which is connected with a small accessory tubercle 
partly filling the first valley. The second and third crests consist of two main cusps, 
each partly divided into two transversely arranged tubercles ; there is no tubercle in 
the posterior main valley ; the whole tooth is more clearly lophodout than in the 
other s])ecies. This tooth is easily distinguishable from the last molar of 1\ parvus, 
which consists of only two crests and a talon, which is composed of two large cusps 
(see text-fig. 50 C). 
J/. I and ni. 2 are both trilophodont ; the autero-external cusp in each is connected 
posteriorly with a small cusp in the anterior valley ; the second outer cusp is 
distinctly divided into two tubercles, especially in m. 2. 
Pm. 4 is bilo])hodont, ynn. 3 a simple compressed cone with small anterior and 
])OSterior cingular ridges. The length of the symphysis is uidcnown. 
1^'urm. ct’ hoc. — Tluvio-mariue beds (Upper Eocene) : north of Birket-el-Qurun. 
