LÖNNBERG, ON A NEW ORYCTEROPUS FROM NORTHERN CONGO. 7 



In O. afer the greatest occipital width of the skull is 

 considerably less than the width of the skull at the point 

 vvhere the Sutura fronto-lacrimalis enters the orbit, while in 

 O. erikssoni both these measurements are about equal. In 

 this respect the latter agrees with O. cethiopicus (and, to judge 

 from Andrew's figure, also with O. gavdryi) and O. haus- 

 sanus. 



In O. cethiopicus and afer the brain-case is somewhat con- 

 strieted anteriorly, so that the width across the upper sur- 

 face of the parietalia. at their anterior end just behind the 

 py-oc. postorbitales or a t sutura coronalis is a good deal less 

 than their width a t the hindend, that is than the distance 

 posteriorly from one parieto-squamosal suture to the other. 

 In O. erikssoni, on the contrary, no such constriction makes 

 itse]f known, but the measurement across the parietalia at 

 sutura coronalis is fully equal to that at their hindend be- 

 tween the parieto-squamosal sutures of either side. 



The postorbital processes are comparatively much better 

 developed in O. cethiopicus than in O. afer, haussanus and 

 erikssoni which becomes apparent by comparing the measure- 

 ments in the table indicating the width of the skull just be- 

 hind these processes and those giving the distance between 

 the tips of the latter. The last mentioned species has evi- 

 dently comparatively the shortest proc. postorbitales and they 

 are also thick and blunt. On the other hand the situation 

 of these processes is rather low in O. erikssoni so that the 

 distance between their tips and the zygomatic arches is com- 

 paratively shorter than in O. cethiopicus and afer, in the first 

 it is only about 9,4 7o of the basi-cranial length, in the second 

 11,7 7o and in the third 12.3 of the same dimension. 



The strong development of the parietal region of the 

 skull in O. erikssoni makes itself apparent in that the length 

 of sutura sagittalis is about equal to that of sutura frontalis 

 (fig. 2), but in O. afer as well as in O. cethiopicus the latter 

 suture is decidedly longer than the former. My friend Pro- 

 fessor Matschie has kindly communicated that he has skulls 

 of Orycteropus from Togo and German East-Africa which in 

 this respect resemble O. erikssoni. The latter has, how- 

 ever, a much larger nose so that the length of sutura fron- 

 talis is only 56 7o of the length of sutura nasalis, while 

 according to Matschie the former suture in the other 



