HTiENODON.— PTEEODON. 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 with this, and no doubt 

 belonging to the same jaw, is a third right lower molar. The crown of this tooth 

 consists of two high secant cusps, which together form a cutting-blade : the posterior 

 cusp is the larger and considerably the higher of the two. 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 worn, the direction of wear 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 Hyoenodon, especially in the presence of the small 

 antero-external tubercle and the absence of the talon; the posterior cusp, however, is 

 shorter and higher than in the other species. This specimen seems to be sufficient 

 to show that remains of a Carnivore referable to the genus Hycenodon or some closely 

 allied type exist in these beds, though insufficient to justify the establishment of a new 

 species. ' 



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



C. 8812-3. Fragment of anterior part o£ right ramus of mandible and a last lower molar. The 

 dimensions (in centimetres) of the tootli are : — Length Vd, width '1 , height of posterior 

 lobe 1-1. 



Genus PTERODON, de Blainville. 

 [Ann. Fran?, et Strang. d'Anat. et Phys. vol. iii. (1839) p. 23.] 



1885. Hemipsalodon *, Cope, Amer. Naturalist, vol. xix. p. 163. 



1887. P seudopterodon *, Schlosser, Beitr. Pal. u. Geol. Oesterreich-Ungarns u. d. Orients, vol. vi. 

 p. 201; also vol. viii. (1890) p. 71. 



This genus has hitherto been recorded only from the Eocene of Europe. In the 

 upper jaw the third molar is small and transversely elongated. The first and second 

 molars have an antero-external cusp, wanting in Hycenodon, 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 jaw is relatively 

 short and heavy. 



Only one species at present known from Egypt. 



* Fide Matthew, Bull. Amer. Mus. Nat. Hist. vol. xiv. (1901) p. 20. 



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