ANCODON GOEEINGEI, 179 



Ancodon gorringei, Andrews & Beadnell. 

 [Plate XVIII. figs. 1, 2, 3; text-figs. 60, 61.J 



1902. Ancodus gorringei, Andrews & Beadnell, A Preliminary Note on some new Mammals from 

 the U[)per Eocene o£ Egypt (Survey Dept., Cairo), p. 7. 



Type Specimen. — A mandible wanting the ascending ramus of the left side 

 (PI. XVIII. figs. 1, 1a); Geological Museum, Cairo. 



This is the larger of the two species found in these beds. The extreme length 

 of the jaw exceeded 34 cm. ; the length of the symphysis 9 cm. ; length of the molar 

 series 7-2 cm. Remains are fairly common, and, in addition to the lower jaw and 

 dentition, the upper molars and premolars, some vertebrae, limb-bones, and tarsals 

 are known. 



Form. 8c Log. — Fluvio-marine beds (Upper Eocene) ; north of Birket-el-Qurun. 



C. 8629. Mandible, wanting ascending ramus on left side. On the left side only the molars are 

 preserved, but on the right there are also i. 1, i. 3, pm. 2, j^m. 3, and join, i ; i. 2 and c. 

 are represented by their alveoli only, pm. 1 by its broken base. Type specimen 

 described by Andrews and Beadnell, loc. cit. Figured on PL XVIII. figs. 1, 1a. 



This mandible is very long, owing mainly to the great elongation of the spout-like 

 symphysis {sym.), the upper surface of which is gently concave from side to side, while 

 the ventral surface is convex in the same direction with a slight median ridge, which 

 forms a small projection posteriorly. This form of the ventral surface of the symphysis 

 differs considerably from that seen in A. velaunus, in which not only is this region 

 somewhat shorter, but the posterior portion of the ventral surface is flattened in front 

 and concave behind. The horizontal ramus is slender ; its ventral border, which is 

 thickened and rounded from side to side, is nearly straight from before backwards 

 beneath the premolars and slightly convex beneath the molars. Behind this the ventral 

 edge thins and is slightly concave, and then passes down into the rounded angle of 

 the jaw, which does not form a vertical process projecting considerably below the 

 rest of the mandible as in some species, e. g. A. bvvinus and A. aymardi. The outer 

 face of the horizontal ramus beneath the premolars is concave from above downwards, 

 beneath the molars it is flat or slightly convex ; its greatest depth is beneath the last 

 molar. Behind the last molar the rami diverge rapidly. The anterior border of the 

 ascending ramus is convex and slopes back to the summit of the coronoid process {cor.\ 

 the posterior border of which is slightly concave ; it rises considerably above the level 

 of the condyle (cond.^, which is transversely elongated and is convex from before 

 backwards and nearly flat from side to side. The posterior region of this mandible is 

 imperfectly preserved. 



The incisors are procumbent: i. 1 is the smallest; i.2, here wanting, was probably 

 the largest ; i. 3 has a small hastate crown, the lower face of which is strongly convex, 

 the upper flat or gently concave ; the root is relatively very large. The canine 

 (represented by the alveolus only) is separated in Iront from i. 3 by a short diastema 

 ("8 cm.) and behind from pm. 1 by a longer interval (22 cm.). Pm. 1 is represented 



2a 2 



