IlTyENODON.— PTEKODON. 
219 
This genus is represented by a single specimen only, consisting of the anterior part 
of a right ramus of a mandible with the alveoli of the large canine and the anterior 
premolars, the roots of the latter being in situ. Associated Avith this, and no doubt 
belonging to the same jaAV, is a third right lower molar. The crown of this tooth 
consists of tAvo high secant cusps, Avhich together form a cutting-blade: the posterior 
cusp is the larger and considerably the higher of the tAA^o. On the antero-external face 
of the anterior cusp near its base there is a small adherent tubercle ; there is no talon, 
though the cingulum is slightly developed on the posterior angle of the tooth. The 
outer face of the tooth is considerably Avorn, the direction of AA^ear being such that the 
cutting-edge remains sharp. This tooth is similar in general form to the last lower 
molar of the European species of Ilycenodon, especially in the presence of the small 
antero-external tubercle and the absence of the talon ; the posterior cusp, hoAvever, is 
shorter and higher than in the other species. This specimen seems to be sufficient 
to shoAV that remains of a Carnivore referable to the genus Hymiodon or some closely 
allied type exist in these beds, though insufficient to justify the establishment of a neAv 
species. 
Form. & Log. — Fluvio-marine beds (Upper Eocene) : north of Birket-el-Qurun. 
C. 8812-3. Fragment of anterior part of right ramus of mandible and a last loAver molar. The 
dimensions (in centimetres) of the tooth are: — Length 1'3, width ’7, height of posterior 
lobe IT. 
Genus PTERODON, de Blainville. 
[Ann. Fran^, et Etrang. d’Anat. et Phjs. a'oI. iii. (1839) p. 23.] 
1885. IJemipsalodon *, Cope, Amer. Naturalist, vol. xix. p. 163. 
1887. P seudopterodon *, Schlosser, Beitr. Fal. u. Geol. Oesterreich-Ungarns u. d. Orients, vol. vi. 
p. 201 ; also vol. \dii. (1890) p. 71. 
This genus has hitherto been recorded only from the Eocene of Europe. In the 
upper jaAV the third molar is small and transverselyeiongated. The first and second 
molars have an antero-external cusp, AA^anting in Ilycenodon, and the posterior lobe of 
the cutting-blade is smaller. In the lower molars there is no postero-internal cusp, 
but there is a small cutting-talon. M. 3 is much the largest. The jaAv is relatively 
short and heavy. 
Only one species at present knoAvn from Egypt. 
* Fide Matthew, Bull. Amer. Mus. Nat. Hist. vol. xiv. (1901) p. 20. 
