OCR Text |
Show 1882.] PROF. ST.-GEORGE MIVART ON THE ALUROIDEA. 467 may have a somewhat larger aperture, as in the Herpestina and Proteles; or the septum may be represented only by two osseous ridges tending to divide off a small anterior chamber in each bulla, as in Hyana. The two chambers of the bulla may be placed, one rather internally and the other externally, as in the Felida and Herpestina; or one behind the other, as in the Viverrina. If placed one internally and one externally, the more posterior (which does not contain the auditory ossicles) may be placed the more internally, as in the Felida, or the more externally, as in the Herpestina. The external chamber may be not merely placed the more externally, but may be posteriorly and strikingly everted outwards, as in the Herpestina. The bulla may narrow much anteriorly, as in Paradoxurus. Its anterior chamber may be hardly bullate, as in Cynogale, or very decidedly so, as in Genetta and Herpestes. The external auditory meatus is generally very short, but may be prolonged, as in Suricata and Hyana. Its posterior margin may project the more, as in most Viverrina, or its anterior margin, as in most Herpestina, or its inferior part, as in Hemigalea. The floor of the meatus may be imperfectly ossified, as in Suricata (where there is a longitudinal fissure) and in Herpestes (where there is a foramen). Instead of a fissure or foramen there may be a deep groove, as in the Galidictina. The external aperture of the auditory meatus may be large and rounded, as in Felis; or oval, as in many Viverrina; or small and triangular, as in Herpestes and Suricata. There may be a very deep pit (to receive the hyoidean cornu) on the outer side of the bulla, just below the external auditory opening, as in Arctictis. The mastoid may be prominent, as in Felis, Hyana, and Suricata ; or not at all so, as in most Viverrina. The paroccipital process may not depend below the bullae or may be very slightly prominent, as in Felis. It may depend below the adjacent part of the bulla as a distinct process, as in Viverra civetta and most Viverrina; or it may not do so at all, as in the Herpestina. Sagittal and lambdoidal ridges may be greatly developed, as in the large Cats, and especially in the Hyaenas ; or they may be almost evanescent, as in Eupleres, where also the zygomata are very slender. The occipital region may be very exceptionally prominent in the middle, as in Eupleres. The mesopterygoid fossa may be to the cranial length at 100 as 23*9 (as sometimes in Felis), or only as 11"] (as sometimes in Herpestes). The average breadth of the palate compared with its length in the Felida is as 80*2 to 100. It may be only 32*5, as in Eupleres, or 33*8, as in Cynogale. It is 62*5 in Genetta, and 51*3 in Viverra civetta. It is 87*4 in Crocuta. In Suricata it is 65*6. An alisphenoid canal may be present, as always in the Viverrina (except generally in Viverricula) and in the Herpestina (save in |