In the article CARNIVORA (vol. i. p. 478.), the remarks on the teeth are limited chiefly to their physiological adaptations. A description of some of their more remarkable structures will here be given, according to the idea of the nature of the teeth above developed. The dental formula of the dog, jackal, wolf, and fox, is illustrated in fig. 580, III. CANIS.
In the Megalotis, or Long-eared Fox (Oto eyon, Licht.), the deviation from the typical dentition of the Canidce is effected by excess of development ; two additional true molars being present on each side of the upper, and one on each side of the lower jaw, in the permanent series of teeth ; and an approach is made by the modified form of the sectorial molar and of some of the other teeth to the dentition of the Viverridce. This family of Carnivore, which comprehends the Civets, Genets, Ichneumons, Musangs, Stirikates, and Mangoes, is characterised, with few exceptions, 1-1 by the following formula : — i. ; c.
4-4 2-2 p. ; 711. = 40. It differs from that of the genus Canis by the absence of a tubercu lar tooth (nt. 3) on each side of the lower jaw ; but, in thus making a nearer step to the typical carnivorous dentition, the Viverridce, on the other hand, recede from it by the less trenchant and more tubercular character of the sectorial teeth, as is shown in the figures of the teeth of the Viverra indica, in my " Odon tography," pl. 126. figs. 1, 2, and 3.
The canines are more feeble, and their crowns are almost smooth ; the premolars, however, assume a formidable size and shape in some aquatic species, as those of the sub genus Cynogale, in which their crowns are large, compressed, triangular, sharp-pointed, with trenchant and serrated edges, like the teeth of certain sharks, (whence the name Squalodon, proposed for one of the species), and well adapted to the exigencies of quad rupeds subsisting principally on fish : the op posite or obtuse, thick form of the premolars is manifested by some of the Musangs, as Paradoxurus auratns. The upper sectorial tooth, p. 4, is characterised by having its inner tubercle larger, the middle conical division of the blade thicker, and the posterior one smaller than in the genus Canis. This tooth advances
to beneath the ant-orbital foramen in the Mu sangs (Paradoxurus): it is situated farther back in the Civets and Genets, in which the blade of the sectorial is sharper. This shows that relative position to the zygomatic or molar process of the maxillary is not a good cha racter.
In the lower jaw the sectorial tooth (nz. 1) manifests its true molar character by the pre sence of an additional pointed lobe on the inner side of the two lobes forming the blade at the fore-part of the crown : the posterior, low, and large lobe of the tooth being also tri-tuberculate, as in the dog. The last molar (M. 2) has an oval crown with four small tubercles, resembling the penultimate lower molar in the dog, with which it corresponds.
The deciduous dentition consists, in the Viverrine family, of: incisors ; canines ' molars l • = 28. If the first per 1 3 3-33 manent premolar has any predecessor, it must be rudimental and disappear early in both jaws ; the second premolar displaces the first normally developed deciduous molar ; the third upper premolar displaces and suc ceeds the deciduous sectorial, which has a sharper and more compressed blade, and a relatively smaller internal tubercle, than the permanent sectorial. This tooth displaces the last deciduous molar, which is a tubercular tooth, resembling in form the first of the two upper permanent tuberculars ; these coming into place without pushing out any prede cessors, enter into the category of true molar teeth. In the lower jaw the third premolar displaces the deciduous sectorial, which has three trenchant lobes and a relatively smaller posterior talon than the permanent sectorial. The fourth premolar displaces the third or tubercular milk-molar. The permanent sectorial and tubercular molars displace no predecessors, and are therefore vi. 1 and m. 2.
The first premolar, p. 1, is not developed at any period in the Mangues (Crossarchus), the Suricates (Ryzcena), or the Itiang,usta pahalinosa ; these Viverrines, therefore, retain throughout life more of the immature cha racters of the family, and in the same degree approach in the numerical characters of their dentition to the more typical Carnivora.