EXTERNAL CHARACTERS OF MONGOOSES. 351 



The Ear, Vibrissce aitd lihinarium. 



The Ear. — The only description of the ear of Mongooses with 

 which I am acquainted is that of Boas (' Ohrknorpel und ausseres 

 Ohr der Siiugetiere,' p. 140, pi. xxi. iig. 222, Kopenhagen, 1912), 

 who examined this organ in the common Indian species ZTer^estes 

 griseus ( = Mungos mungo). 



The ear differs in the following particulars from that of all the 

 genera of Viverridse discussed in my previous papers : — (1) The 

 marginal bursa is absent ; (2) the siq^ratragus or plica 2irincipalis 

 is converted into a large movable laminate flap ; (3) above the 

 supratragus there is a similar but smaller flap ; (4) the antero- 

 internal ridge curves abruptly backwards into the cavity of the 

 ear, its inferior prominence being set high up and fitting into a 

 hollow above the antitragus. By the disposition of these ridges 

 the cavity of the ear is capable of being very completely closed 

 when the ear is folded. The superior flap closes over the space 

 above the supratragus, the latter similarly shuts down upon the 

 antero-internal ridge, and the prominence of the latter fits into 

 the space above the antitragus, which is itself applied to the ridge 

 representing the tragus. 



In nearly all the genera the ears are set well behind the eye, 

 are irregularly semicircular in shape, and small, so that the upper 

 margin hardly projects above the line of the occiput and of the nape 

 of the neck ; but in Cynictis they are much larger, project well 

 above the head, and have the antero-superior rim rising only a 

 little behind a point above the posterior angle of the eye. In its 

 structural details the ear in this genus is of the same general 

 type as that seen in Mungos, Crossarchus, Bdeogale, and others, 

 with the exception that there is a small shallow pocket behind 

 the antitragus (text-fig. 3, A, C). I have not observed this in 

 any other genus, but it is no doubt the homologue of the similarly 

 situated depression in the Hysenas, which was regarded by Boas 

 as the representative of the marginal bursa in other ^luroid 

 Carnivores. 



It is perhaps significant that this remnant of the bursa 

 persists in the genus which of all the Mongooses has the longest 

 and broadest ears and approaches, in that respect at least, nearest 

 to the Hytenas. Nevertheless, the ear of the Hysenas, except 

 for the abnormal position and structure of the bursa, resembles, 

 broadly speaking, that of other ^luroidea *. Some species of 

 Mungos, e. g. M. gracilis (text-fig. 1, A), have much larger ears 

 than species like M. micngo and M. smithii. In Ichneumia albi- 

 cauda (text-fig. 1, D) they are also tolerably large ; whereas in 

 Atilax paludinosus (text-fig. 1, C), Ariela fasciata and Cross- 

 archus obscurus (text-fig. 2, A, B) they are comparatively small 

 and rounded. Nevertheless, whatever their size may be, the 

 «ars conform closely to the type described in Mungos mungo and 

 M. smithii. 



* See Ann. Mag. Xat. Hist. (8) xvii. p. 333, 1916. 



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