Proceedings of the Scientific Meetings of the Zoological Society of London 1869

Page 40

20 MR. W. H. FLOWER ON THE [Jan. 14, permanently distinct and moveable, not only from the other cranial bones, but also from the tympanic portion of the bulla. In form it is conical, broad and truncated behind, pointed in front, and rather compressed at the sides, which meet in a ridge. The orifice between the two cavities of the bulla is very minute, and the septum perma­nently double, receiving a stratum from the wall of each cavity. The carotid canal is distinct, situated near the anterior end of the inner wall of the posterior chamber of the bulla ; but it appears to be never completely closed on the inner side, except by the contiguous basioccipital. The paroccipital and mastoid processes are as in the Civet. The condyloid foramen is even more concealed. The glenoid foramen is very minute. The alisphenoid canal is distinct. In a specimen of Nandinia binotata in the College Museum, which otherwise agrees generally with Paradoxurus, the posterior chamber is entirely cartilaginous, although the cranium appears to be adult or nearly so, and the tympanic portion of the bulla is completely ossified. Cynogale, which has a singularly modified dentition, closely resem­bles the Paradoxures in its cranial characters, even to the permanent want of union of the two portions of the bulla. The anterior cham­ber is very small and flat; the posterior rather more inflated and conical than in Paradoxurus, being more like that of Viverra. The carotid canal forms a deep groove, converted into a foramen by the lip of the basioccipital, placed rather in front of the middle of the posterior chamber. The paroccipital process projects beyond the bulla. There is no alisphenoid canal. All the Herpestine members of the Viverridce (Cynopoda, Gray) present certain common characters of this region by which they can be readily recognized. The bulla (fig. 9, p. 21) is very prominent and somewhat pear-shaped, the larger, rounded end being turned back­wards and somewhat outwards ; a well-marked transverse constriction separates the chambers, which are now directly anterior and posterior. In front of the constriction the anterior (true tympanic) chamber is somewhat dilated again, much more than in the Civet-like Viverrines. The aperture of communication between the two chambers is rather larger. The carotid canal (car) is very distinct, situated quite at the front of the posterior chamber. The paroccipital process (p) does not project beyond the bulla, but is spread out and lost (in adult animals) on its posterior surface. The condyloid foramen (c) is concealed ; the glenoid foramen is very minute or absent. The ali­sphenoid canal appears to be always present. The Suricate (Rhyzcena zenik) presents the same essential charac­ters in a very modified form, caused by the general lateral expansion of the posterior part of the cranium. Here, and here alone amono-the Viverrida?, there is a prolonged auditory meatus ; but it presents the peculiarity of being fissured along the whole extent of the middle of its floor*. The anterior chamber is remarkably prominent, even more than the posterior. Externally these parts have some resem­blance to those of the Arctoidea, but show their adherence to the Viverroid type in the two distinct chambers of the bulla, the ex- * The slightly produced floor of the meatus of Urva is also fissured.