African and S.- American Otters. 389 



Skull: basal length 128 mm.; zygomatic breadth 01'5; 

 mastoid breadth 92-5 ; breadth of brain-case exclusive of 

 mastoid flange (I(j ; breadtli of" nasal opening 18; interorbital 

 breadth 27 ; tip to tip of postorbital processes 30o ; inter- 

 temporal breadth 25'5 ; palate length 'o'o ; antero-posterior 

 diameter of ^7* 12'9 ; greatest diameter of m^ 18, antero- 

 })Osterior diameter of its inner lobe 13 ; greatest height of 

 zygomatic arch 10. 



//ah. Coporolc R., Angola. 



7'i/pe. Adult female. B.M. no. 98. 3. 20. 1. Collected 

 by Mr. G. W. Penrice. 



I have hitherto not ventured to determine definitely this 

 fine otter, partly owing to its being a female and partly for 

 want of good S. -African material for comparison. 



Now, however, that the Museum possesses a good adult 

 pair of skulls of the nearly allied A. c. /lindet oi Ei. Africa, 

 from which the differences due to sex can be estimated, and 

 a good skull of tlie true S. -African capensis has been described 

 and measured in Prof. Einar Lonnberg's recent interesting 

 paper on the subject *, I am in a position to determine the 

 Angolan form. 



So far as sex is concerned, there appears to be remarkably 

 little difference between male and female in the general out- 

 lines of the skull, the male having merely much more heavily 

 roughened bones and larger crests and processes for the 

 attachment of muscles. But the breadth as compared with 

 the length measurements are practically the same in both 

 sexes. 



If therefore, as we may presume, the male L. c. angohv has 

 the same general proportions as the female, it will be readily 

 seen from the above measurements and from those given in 

 Prof. Lonnberg's paper how markedly the new form differs 

 from any African otter hitherto described. As it happens, 

 the chief length measurement is exactly the same in the type 

 of angol(e and in Prof. Lonnberg's Natal example, while the 

 zygomatic breadth is actually 13 mm. and the mastoid breadth 

 10 mm. less in the former than in the latter, a difference 

 which naturally produces a very considerable alteration in 

 general outline. Jiut I suspect that the roughening of the 

 bones and increase of the processes in the male will result in 

 enough assimilation to A. capensis to justify my considering 

 the Angolan otter as only a subspecies of that widely spread 

 form. 



♦ ' Arkiv fcir Zoolo^,'!,' iv. no. 1:2 (1908). 

 Ann. tO May. .V. /list. Ser. 8. Vol. i. 26 



