Vol. 70.] VERTEBRATES FROM BRITISH EAST AFRICA. 17L 



surrounded by enamel are formed in each crest, the larger outer 

 islands being crescentic and situated immediately internal to the 

 paracone and metacone respectively. The smaller islands are 

 situated just external to the protoeone and hypocone ; in wear, the 

 latter tubercle becomes continuous with the posterior wall of 

 the tooth. The anterior and posterior faces of the tooth are tlat, 

 with a band of cement near the outer edge ; the inner face is slightly 

 concave from above downwards, the outer correspondingly convex. 

 There is a slight increase of size in the tooth towards the roots, of 

 which there seem to have been four. 



The dimensions (in millimetres) of these specimens are : — 



Mandible : 



Length of the grinding- surface of the four teeth 12 



Length of the specimen as a whole 17 



Height of crovm 



Lower teeth : Length. Width. (outer side). 



?pm<3 1-7 1*1 1-8 



(?)pm4 3-1 1-3 3-0 



(?)ml 3-5 1-8 5-0 



(?)m2 3-1 2-0 6-0 



Upper molar 4*0 3*0 5 - 



If this animal is rightlv regarded as a Hvracoid, it differs from 

 the other members of the group in (1) its very small size, and (2) 

 the extreme hypsodonty of its molar teeth. I propose to refer this 

 species to a new genus, 31 1/ olnj rax, under the specific name 

 J£. oswaldi. It must also be regarded as the representative of 

 a new family, the Myohyracidae. The fact that in the Upper 

 Eocene (Oligocene of most authors) of Egypt the Hyracoidea 

 were already represented by a great variety of forms with widely 

 ■differing types of dentition, shows that they were a group of 

 great importance and plasticity, and so there is nothing remarkable 

 in finding a type such as is here described in beds of Lower 

 Miocene age. Probably, when the early Tertiary faunas of Africa 

 are better known, many other striking modfiications of the same 

 group will be found. 



ARTIODACTYLA. 



Family Anthracotheriid.e. 



This group is represented by portions of the skeleton of at least 

 two species of Anthraeotheres. The specimens include a fragment 

 of a mandible with m 3 in situ, humeri, portions of tibiae, carpals, 

 and tarsals. 



The fragment of mandible ( PI. XXIX, figs. 3 a & 3 I ) from Bed 31 

 •consists of the hinder portion of the left ramus with the last molar 

 •complete, except for the loss of the postero-intemal cusp, and the 

 roots of the second molar. The molar is a comparatively hvpsodont 

 tooth, approximating in this respect to the molar of Ancodon. The 

 inner cusps are particularly high and sharp-pointed ; the outer 



