20 ARKIV FÖR ZOOLOGI. BAND 3. N:0 3. 



than the straight upper part of the same contoiir, but in 

 O. erikssoni the straight part is very much longer than the 

 other distance^ which of course results in a very different 

 shape of the whole bone. 



In O. erikssoni the crista deltoidea of the humerus is more 

 strongly developed than in O. af er and extends fnrther down- 

 wards. 



Ulna and radius are very strong but their general shape 

 is as in O. af er. 



Ala ossis ilium has anteriorly at its inferior edge a trian- 

 gulär processus from which linea arcuata interna proceeds 

 backwards. In front of the acetabulum the posterior end 

 of linea arcuata externa forms a very large tuber cle. 



a. b. 



Fig. 7. Right astragalus of O. erikssoni. a. from above, b. from below. 



V-' nat. size. 



Tuherculum iliopectinceum of the pubic bone is still largcr, 

 but the differences of the pelvis of this species and that of O. 

 afer make themselves mostly known with regard to size. 



Trochanter major of the femur is not raised above the level 

 of the caput but trochanter minor is stronger than in O. afer. 



The astragalus is perforated as is seen in the accompa- 

 nying figure (fig. 7 a & b). 



The dimensions of different parts of the skull compared 

 with the corresponding ones of other species and the dimen- 

 sions of several bones of the skeleton compared with those 

 of O. afer are recorded below in the table of measurements. 

 In the latter case I ha ve only quoted Cuviers measurements 

 as he has had a very large specimen of O. afer, even larger 

 than the two specimens of this species I have had for com- 

 parison. The difference in size becomes therefore very im- 

 portant. 



^ Althougb proc. coracoideus is directed niore downwards in O. eriks 

 soni which, of course, increases the latter measurement. 



