EXTERNAL CHARACTERS OF MONGOOSES. 355 



of excluding dust and dirt without at the same time excluding 

 sound-vibrations to the same extent as does the arrangement for 

 folding seen in Suricata. 



Facial Vibrissce. — In number and disposition the tufts of 

 vibrissse are quite normal and agree with those of the Viverridse. 

 But they vary a good deal in development in different forms. 

 Broadly speaking, they are longer and more numerous in smaller 

 than in larger species, as may be seen by comparing Mungos 

 gracilis with M. mungo or Ichiieumia albicaada with Ariela 

 fasciata and Crossarchus ohscurus. For instance, the upper 

 genal tuft consists of about three bristles in Af, gracilis and 

 Ariela fasciata, and generally at all events of only one, which is 

 not always detectable, in M. mungo and Ichneiwiia. 



An exception to this generalisation is seen in Atilax ixdu- 

 dinosKjS, one of the largest members of the group. The normal 

 vibrissse are long, and the anterior mystacials and the submentals 

 are unusually copious and long, giving to the muzzle a hirsute 

 appearance not seen in other species where these particular 

 bristles are comparatively poorly developed (text-figs. 1, 2, & 3). 



Rhinarium. — This organ presents no features by whicli it can 

 be distinguished from that of all genera of Viverridse. Within 

 the group of the Mongooses it is tolerably constant in form. Its 

 upper anterior margin, viewed from above, is evenly convex from 

 side to side and not mesially notched or sulcate ; from the front 

 it is nearly straight or lightly convex, with rounded angles. On 

 the upper surface the narial slits converge slightly, or somewhat 

 markedly, as in Atilax, and are bordered externally by a narrow 

 rim of naked integument ; the posterior border is usually lightly 

 concave, but in Atilax the hairs of the muzzle overgrow it 

 to a greater extent, forming an angular excision in the naked 

 skin. The infranarial portion of the anterior surface is always 

 well developed, and generally transverse from side to side along 

 the lower margin ; but in Atilax paludinosus, in which the 

 whole rhinarium is broad, the infranarial portion is especially 

 deep and its edges diverge a little upwards and outwards from 

 the middle line. The median sulcus, with which the anterior 

 surface is marked in some forms, never appai-ently passes higher 

 than the upper edge of the nostrils. 



As has been pointed out by Gray, Thomas, and others, the 

 inferior edge of the rhinarium may or may not be continued 

 down the middle line of the upper lip as a strip of naked skin. 

 This strip is present in the genera Mungos, Helogale, Ichneumia, 

 Atilax, Bdeogale, and Cynictis*, and absent in Rhynchogale '^ , 

 Ariela, Crossarchus, and Suricata, in which the skin of the 

 upper lip is continuously hairy across the middle line. When 

 this strip is present, it is always grooved, and in a great majority 



* In tlie 'Fauna of South Africa,' Mamm. i. p. 73, 1900, Mr. W. L. Sclater places 

 Ci/nictis, with Suricata and Cy'ossarchus {= Ariela), in the category in which the 

 lip is undivided. This is an error. 



t I have never seen a fresh or alcohol-preserved adult example of this genus. 



