LÖNNBERG, ON A NEW ORYCTEROPUS FROM NORTHERN CONGO. 1 1 



distance from the a] veolar plane which is much less than Vä of the 

 distance between proc. condyloideus and proc. angularis (fig. 4). 

 The mandible of O. erikssoni is, to correspond with the 

 length of the upper jaw, very long and its ramus horizontalis 

 is comparatively longer than in the other species, while ramus 

 adscendens is comparatively shorter. In O. erikssoni it is 

 only 39 7o of the length of the whole mandible but in O. 

 afer 42 to 44 %, in O. senegalensis 42 ^/o and in O. cethio- 

 picus 47 7o- Ramus adscendens of the mandible is also com- 

 paratively more slender in O. erikssoni than in the others as 

 the greatest breadth across the former is contained about 

 5 72 times in the greatest length of the mandible of this new 

 species, but the same relation in O. afer is only 4 Vi* to 4 7» 



Fig. 4. Right half of mandible of O. erikssoni.- \-2 nat. size. 



and in O. cethiopicus even 4 Vt. The absolute measurements 

 of the breadth of ramus ascendens of the mandible, of O. 

 erikssoni and O. cethiopicus are almost equal resp. 41 and 42 

 although the length of the skull in the former case is 278 

 mm. and in the latter only 204 mm. 



There are 6 teeth above and below on either side in O. 

 erikssoni. The foremost ones or premolars appear to be less 

 reduced in size compared with those of O. afer and O. cethio- 

 picus. In the latter two species these foremost rudiments 

 of teeth are (at least in my material) separated from the 

 others by a somewhat larger interspace. This is, however, 

 not the case in O. erikssoni in which they form continuous 

 seiies with the others (fig. 3). 



