Skuf/s of (lie Felidaj cnuf ViviMiidie. 2^5 



ratine; tlio wall of tlip bulla above tlio basioccipital bone. 

 'rUc. canal itsflC tlirou^^lioiit its Icnj^th is a narrow cylimlriual 

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

 iiowjiere in contact witli the basioccipital or the periotic. 

 The artery 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-intcrnal angle of the bulla, as in Crtj])tuprocta. 



Within the limits of the genus Miiuyos the j)osition of the 

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

 ichiieio/ion it lies about midway between the foramen lar.erum 

 posticuin and the anterior termination of the canal ; but in 

 a skull of Mungos sm'ithii the posterior orifice is only a short 

 distance in front of the foramen lucerum posticuin, so that 

 the canal iu this example is relatively much longer than 

 in the other. 



Judging from a superficial examination of tiie 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 

 juNt 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 ehamioer is 

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

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

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

 the anterior chamber is small and the posterior large, the 

 posterior onficeof 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- 

 tina3 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 binotata) the bulla, 

 as is well known, has the wall of the posterior chainl)cr 

 permanently cartilaginous. In a fresh example of this 

 species I found the carotid artery entering the cartilaginous 

 bulla a little way in front of the foramen lacerum pusticuni, 

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

 orcipital 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 [)lace. This 



