264 Mr. R. I. Pocock on the 



portions of the tympanic, periotic, and basioccipital ; and 

 the foi'amen lacerum medium is a rather short constricted 

 notch in the basisplienoid, and is visible to a great extent 

 upon the surface of the skull. It may be added that the 

 two bones composing the tympanic bulla are completely 

 separated in the adult skull, as they are in the examples of 

 Paguma larvata and Paradoxuriis niger examined. 



In a subadult skull of Arctogalidia with the tooth-change 

 just completed, but with the basisphenoidal suture still 

 visible, the posterior orifice of the carotid canal lies approxi- 

 mately midway between the foramen lacerum posticum and 

 the foramen lacerum medium. It leads into a groove in the 

 tympanic, which is bordered on the admedian side by the 

 basioccipital ; but anteriorly it is continued by a complete 

 bony tube formed by the tympanic, as in Genet ta felina and 

 Paguma larvata. But, unlike the other species hitherto 

 discussed, the orifice by which the carotid artery enters 

 the skull is entirely cut off from the periotic, and pierces the 

 sphenoid as a lound hole, which is exposed on the base of 

 the skull just in front of the antero-internal angle of the 

 tympanic bulla. The two bones of the bulla are completely 

 fused togetlier, as iu Arctictis, Genetta, Viverra, Viver- 

 riculu, and Civettictis. 



In (Jynugale the course of the carotid canal is peculiar. 

 It runs from a notch-like orifice in the wall of the bulla 

 obliquely across the posterior chamber as a very distinct 

 crest to the septum and periotic, and itself forms a low 

 partition to that chamber. The foramen lacerum medium 

 simply notches the basisphenoid. 



In Cryptoprocta ferox the features presented by the carotid 

 canal combine those of Genetta -dwA Arctogalidia. The canal 

 slants as a groove on the tympanic near the middle of the 

 inner wall of the bulla ; but where it dips beneath the surface 

 it is converted into a complete cylindrical tube formed by 

 the tympanic alone, and is thus cut off from the basioccipital 

 and the periotic. It terminates in front beside the eustachian 

 aperture. The artery enters the brain by a hole, not a 

 notch, in the basisphenoid, and this hole, as in Arctogalidia, 

 is visible on the base of the skull in front of the antero- 

 internal angle of the bulla, and is completely severed from 

 all coiiuection with the periotic. 



Approximately the same condition appears to obtain in 

 Eupleres and Fossa — at all events, so far as the distinctness of 

 the carotid foramen iu the sphenoid is concerned. 



In the skulls of mongooses [Mungos) the posterior orifice 

 of the caual is a small round hole, not a long groove, perfo- 



