14 ARKIV FÖR ZOOLOGI. BAND 3. N:0 3. 



which is proved by the comparatively great development of 

 the parietal region of the skull. As already has been men- 

 tioned in comparing the skull of O. erikssoni with that of 

 other recent species, the former has sutura sagittalis as long 

 as sut. f rontalis, but in O. gaudryi the latter is very much 

 longer, to judge from Andrews figure (1. c. 297). The great 

 specialisation of O. erikssoni again manifests itself in the very 

 great length of its snout and nasal region of the skull. The 

 skull of O. gaudryi described by Andrews was unfortunately 

 mutilated in front, but it seems to have been rather short- 

 nosed. while O. erikssoni appears to be the most long-nosed 

 even among the living species. This prolongation of the 

 snout may be regarded as a specialisation parallel to that 

 exhibited by Myrmecophaga, but it is then of interest to see 

 that in spite of this parallelism O. erikssoni has not reduced 

 its teeth more, but rather less, than the more short-snouted 

 species of the same genus. And with regard to the molars 

 the reduction has not gone far beyond the stage represented 

 by the Pliocene Orycteropus. 



With regard to the skeleton I have a still more restric- 

 ted material for comparison viz. only two skeletons of O. 

 afer. The differences between this species and O. erikssoni 

 are rather striking in many respects and important charac- 

 teristics may be deduced b}^ comparing the two skeletons 

 with each other. A few notes on this subject may therefore 

 be of interest although it cannot be said whether these charac- 

 teristics are shared as well by other species t lian O. erikssoni 

 or not. 



All the bones of the present species are very robust with 

 well developed processes indicating a strongly muscular ani- 

 mal. This general character is conspicuous everywhere and 

 is very pronounced on atlas, which has large transverse pro- 

 cesses (fig. 5) with grooves and crests for the insertions of 

 muscles. The distance between their tips is 76 mm. 



Epistropheus has a very high and broad neutral spine, 

 more erect than in O. afer. Its anterior upper margin mea- 

 sures 51 mm. and the distance from the posterior tip to the 

 medullary canal is 36 mm. A look at the ventral side of 

 epistropheus of this animal (fig. 5) shews very plainly its 

 compound character and at the same time that the centrum 

 of atlas anchylosed to epistropheus forms more than processus 



