GENIOIITUS Minus. — OENTOIITUS EAJUMENSIS. 
105 
noar the anterior end oC the tootli. The second inolar (to. 2) is similar to the first, 
exeo]it that on tlie liinder border there is an additional minute tubercle lying internal to 
the posterior accessory tubercle of the postero-exteiaial cusp. In m. ?> the structure is 
similar, so far as it is preserved, hut the talon is almost entirely broken away. 
The dimensions (in centimetres) of this specimen are : — 
Extreme length so far as preserved . . . 
Length of symphysis 
Distance between end of process and alveolar border 
Width of symphysial region at k 3 . 
The dimensions (in centimetres) of the teeth are 
yTOi. 1 
2')m. 2 
'pm. 3 
pm. 4 
VI. 1 . 
m. 2 . 
m. 3 . 
. 16-2 
ier 
7-2 
2-5 a 
Lengtli. 
Width. 
1-2 
•7 
1-2 
•9 
1-3 
1 
1-3 
1-1 
1-5 
1-1 
1-7 
1-3 
9 
1-5 
M 8541. Plaster cast of the above specimen. 
Made in the British Museum. 
Geniohyus fajumensis, Andrews. 
[Plate XIX. figs. 2, 2 a.] 
1904. Geniohyus fajumensis, C. W. Andrews, Greol. Mag. [5] vol. i. p. 162. 
Type Specimen. — Portion of right ramus of mandible with the premolars well 
preserved (PI. XIX. figs. 2, 2 a); British Museum. 
This species is distinguished from G. minis by (l)its larger size, the premolar series 
measuring 5‘6 cm. in length ; (2) the main cusp being distinctly divided into an inner 
and outer tubercle in pmi. 2 ; (S) the posterior lobe of the premolars being much 
larger and more distinctly selenodont. 
Form. & Log. — ITuvio-marine beds (Upper Eocene) : north of Birket-el-Qurnn. 
M. 8435. Portion of right ramus of mandible with 'pm. 1-4. Type specimen described in Geol. 
Mag. [-5] vol. i. (1904) p. 162. Figured PI. XIX. figs. 2, 2 a. 
The first premolar (pm. 1) is strongly compressed, with a very small anterior tubercle, 
a high main cusp from which three ridges diverge posteriorly, one running down the 
outer face of the tooth, a second back to the anterior arm of the V-shaped posterior cusp, 
the third inwards down the inner face of the tooth. The posterior lobe is distinctly 
selenodont. In prn. 2 the anterior tubercle is larger, and the ridge running inwards 
from the main cusp has a small tubercle on its inner end. The posterior lobe is larger 
than in p??i. 1. Pm. 3 has a still larger anterior tubercle and the cusp on the inner side 
of the main cusp is nearly as large as that element and clearly separated from it ; the 
posterior V is still larger. Pm. 4 is similar, except that the small anterior cusp is 
2 c 2 
