Skulls of the Felidse and Vivenidse. 265 



rating the wall of the bulla above the basioccipital bone. 

 The canal itself throughout its length is a narrow cylindrical 

 bony tube formed by the tympanic, so that the artery is 

 nowhere in contact with the basioccipital or the periotic. 

 The arterj'^ issues from this tube alongside the eustachian 

 aperture, and enters the skull by a conspicuous foramen on 

 the base of the skull, piercing the basisphenoid in advance of 

 the antero-internal angle of the bulla, as in Crijptoprocta. 



Within the limits of the genus Munyos the position of the 

 posterior orifice of the canal varies. In a skull of Mangos 

 ichneumon it lies about midway between the foramen lacerum 

 posticum and the anterior termination of the canal ; but in 

 a skull oi Mungos smithii the posterior orifice is only a short 

 distance in front of the foramen lacerum posticum, so that 

 the canal in this example is i-eladvely much longer than 

 in the other. 



Judging from a superficial examination of the skulls of 

 mongooses of other genera, the structure of the carotid canal 

 is the same as that described above. The position of the 

 posterior orifice, which always apparently pierces the bulla 

 just behind the inner portion of the partition of the bulla, 

 varies in accordance with the length of the two chambers. 

 In Cynictis, for example, where the posterior chamber is 

 very short and the anterior very long, the orifice in question 

 is only a little way in front of the foramen lacerum posticum 

 and the canal is long, whereas in Ichneumia albicauda, where 

 the anterior chamber is small and the posterior large, the 

 posterior orifice of the canal is set far forwards, and the canal 

 itself is short. 



In Galidictis and related genera the structure of the 

 carotid canal appears to be the same as in the mongooses. 



The condition of the canal in the mongooses and Galidic- 

 tinse may be derived from that seen in Cryptoprocta by the 

 growth and subsequent union of the upper and lower 

 margins of the carotid groove on the bulla, to form a cylin- 

 drical tube continuous with the osseous tube, which forms 

 the anterior portion of the canal in that animal. 



In the African palm-civet (^Nandinia hinotata) the bulla, 

 as is well known, has the wall of the posterior chamber 

 permanently cartihiginous. In a fresh example of this 

 species I found the carotid artery entering the cartilaginous 

 bulla a little way in frout of the foramen lacerum posticum, 

 and running over a groove on the periotic close to the basi- 

 occipital and entering the small foramen lacerum medium, 

 which lies deep down and is entirely concealed by the bony 

 tympanic bone, when the latter is left in place. This 



