Vol. 70.] VERTEBRATES FROM BRITISH EAST AFRICA. 173 



The dimensions (in centimetres) of this tooth are : — ■ 



Length in a straight line 9'5 



Length along outside of curve (approximate) ... 13 - 2 

 Width of middle of root 2-5 



The Anthracotheres are also represented b}' several limb-bones, 

 including humeri, a femur, part of a tibia, carpals, and tarsals. 

 Some of these must have belonged to animals considerably bigger 

 than those to which the teeth above described belonged, and 

 indicate that several members of the group lived in this region in 

 Lower Miocene times. 



A very well-preserved humerus (fig. 2, p. 174) of large size 

 probably belongs to a member of this group, and must represent 

 a much bigger animal than those to which the teeth described 

 above belong. In a general way, it is similar to the humerus 

 of BracJiyodtis rugulosus described and figured by Dr. Martin 

 Schmidt, 1 but differs in many details. The articular surface 

 of the head (fig. 2, B, h.) is roughly triangular in outline, one 

 angle projecting posteriorly to a considerable extent ; it is strongly 

 convex from before backwards, and less markedly so from side to 

 side — anteriorly it is separated from the base of the tuberosities 

 by a basin-like hollow. The outer tuberosity (fig. 2,o.f.) is massive, 

 and to some extent overhangs the bicipital groove (b.g.), which 

 does not appear to be the case in Br. rugulosus ; on the other 

 hand, it rises very little above the articular surface as in that 

 species, thus differing from the greater tuberosity of Ancodus as 

 described by Prof. W. B. Scott. 2 In Hippopotamus also the 

 tuberosity rises high above the head of the humerus. The inner 

 tuberosity (i.t.) is massive, and its anterior surface, forming the 

 hinder wall of the bicipital groove, bears a broad convex ridge, 

 which divides the groove into a larger anterior and a smaller 

 posterior portion. 



The shaft of the bone is straight, relatively slender, and some- 

 what compressed laterally. The crista anterior (cr.a., fig. 2, A) 

 running down from the outer tuberosity is not well marked ; but 

 the deltoid ridge (d.r., fig. 2, A) forms a strong anterior prominence 

 situated about the middle of the bone, and in its upper portion 

 hollowed by a roughened concavity. At the distal end there seems 

 to have been a supratrochlear foramen ; this is, however, not quite 

 certain, the very thin wall of bone between the olecranon and the 

 supratrochlear fossae having perhaps been broken away by accident. 

 The trochlear surfaces (t., fig. 2, A & C) are oblique ; the inter- 

 trochlear ridge (i.tr.) is highly developed, and situated well to 

 the outer side of the trochlear groove, so that the outer surface 

 for the radius is considerably narrower than the inner, much as in 



1 ' Ueber Paarhufer der Fluviomarinen Schichten des Fajum ' Geol. Palaont. 

 Abhandl. Jena, vol. xv (1913) p. 200 [48] & pi. xxi [v], figs. 1-3, 11. 



- ' The Structure & Relationships of Amodus ' Journ. Acad. Nat. Sci> 

 Philad. ser. 2, vol. ix (1895) p. 474. 



