6 ARKIV FÖR ZOOLOGI. BAND 7. NIO 9. 



A. C. angolce viz. 66 mm. (Thomas). The postorbital processes 

 are not quite so projecting as in A. capensis but the distance 

 between their tips is much larger than in A. c. hindei and still 

 more so than in A. c. angolce viz. 30,5 mm. (Thomas). In 

 a similar way the interorbital width is similar to that of A. 

 capensis but larger than that of A. c. hindei and A. c. angolce 

 viz. 27 mm. (Thomas). The skull of the Congo race is thus 

 as heavily built as that of its South African ally, and it differs 

 thus considerably from the comparatively slender skull of 

 the Angola race, which geographically is its nearest neighbour. 

 GristcB sagittalis and lambcloidece are well developed. 



The basal parts of the skull of the Congo race are very 

 broad which is proved b}^ the fact that the shortest distance 

 between the longish but rather narrow for. lacera postica is 

 32 mm., but in A. capensis 30, and in A. c. hindei only 27 mm. 

 The said foramina are in both the latter races broader than in 

 the new form. The mastoid processes are directed even more 

 directly downwards than in A. capensis, and with the tip some- 

 what inwards, but they are b}' far not so stout and massive as 

 in the South African race. The antero-posterior diameter of 

 this process a few millimetres above the free end is in the Congo- 

 race 5 mm., and in the South African at the corresponding 

 place 8,5 mm. Squama occipitalis is large, even a little higher 

 than in A. capensis, without counting the crista. The parocci- 

 pital processes are well developed as in A. capensis. With 

 regard to the basicranial characteristics I have onlv been able 

 to compare the Congo skull with such a one of A. capensis 

 and A. c. hindei, from which it is plainly distinct. 



The greatest difference between the new subspecies and 

 all other African Clawless Otters is found by comparing the 

 dimensions of the teeth. Some important measurements of 

 teeth have been published in the descriptions of the different 

 subspecies and these have been put together here to facilitate 

 a comparison with the corresponding ones from the new form. 



Aonyx 

 capensis 



A. c. 



hindei 



A. c. A. c. 



meneliki \angolce 



A. c. 

 congica 



Anteroposterior diameter of p^ 1 14,3 jl2,9 — 14 i — 12,9 11 



17,5-18,2 19,5 



Greatest diameter of m^ . . . ! 20 

 Antero-posterior diameter of its | 



inner lobe \ 14,5 12,1 — 12,3 



18 14 



13 I 9. 



