910 



TEETH. 



chairodus,Jig. 580, VI.*), the series is still fur- 

 ther reduced by the loss of p. 2 in the tipper jaw. 



That the student may test for himself the 

 demonstration which the developmental cha- 

 racters above defined, yield of the true nature 

 and homologies of the feline dentition, the 

 most modified of all in the terrestrial Carnivora, 

 he is recommended to compare with nature 

 the following details of the appearance and 

 formation of the teeth in the common cat. 

 In this species the deciduous incisors d.i. begin 

 to appear between two and three weeks old ; 

 the canines d. c. next, and then the molars d. m. 

 follow, the whole being in place before the 

 sixth week. After the seventh month they 

 begin to fall in the same order; but the lower 

 sectorial molar m. 1, and its tubercular homo- 

 type above (m. 1) appear before d. 2,d. 3, andd.4 

 fall. The longitudinal grooves are very faintly 

 marked in the deciduous canines. The first 

 deciduous molar (d. 2), in the upper jaw is 

 a very small and simple one-fanged tooth ; it 

 is succeeded by the corresponding tooth of the 

 permanent series, which answers to the second 

 premolar ( p. 2) of the hyaena and dog. The 

 second deciduous molar (d, 3) is the sectorial 

 tooth; its blade is trilobate, but both the anterior 

 and posterior smaller lobes are notched, and 

 the internal tubercle, which is relatively larger 

 than in the permanent sectorial, is continued 

 from the base of the middle lobe, as in the 

 deciduous sectorial of the dog and hyaena; 

 it thus typifies the form of the upper sectorial, 

 which is retained in the permanent dentition 

 of several Viverrine and Musteline species. 

 The third or internal fang of the deciduous 

 sectorial is continued from the inner tubercle, 

 and is opposite the interspace of the two 

 outer fangs. The Musteline type is further 

 adhered to by the young Feline in the large 

 proportional size of its deciduous tubercular 

 tooth, d. 4. In the lower jaw, the first milk- 

 molar (d. 3) is succeeded by a tooth (jo.3) which 

 answers to the third lower premolar in the 

 dog and civet. The deciduous sectorial (d. 4), 

 which is succeeded by the premolar (p. 4), an- 

 swering to the fourth in the dog, has a smaller 

 proportional anterior lobe, and a larger pos- 

 terior talon, which is usually notched ; thereby 

 approaching the form of the permanent lower 

 sectorial tooth in the Musteltdce. 



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 \njftg. 580, III. CANIS. 



* Machairodus, from f^. x -'f, a sabre ; and oStls, 

 a tooth. This generic name was imposed by 

 Dr. Kaup on the extinct animal which was armed 

 with canine teeth, like that figured in fig. 580, VI. 

 Such teeth, long, compressed, falciform, sharp- 

 pointed, and with anterior and posterior finely- 

 serrated edges, were first discovered in tertiary 

 strata in Italy and Germany, and were referred by 

 Cuvier to a species of bear, under the name of Ursus 

 cultridens. Fossil canines of this genus have been 

 found in Kent's Hole cave, Torquay. 



In the Megalotis, or Long- eared Fox (Oto- 

 cyon, 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 Viverridcs. This family of 

 Carnivora, which comprehends the Civets, 

 Genets, Ichneumons, Musangs, Surikates, and 

 Mangues, is characterised, with few exceptions, 



3 3 I j 



by the following formula : i. ^ - ; c. ^ - ; 



o o I 1 



44 



22 



= 40. It differs from that 



/" 44 ' "" 22 ' 

 of the genus Canis by the absence of a tubercu- 

 lar tooth (m. 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," pi. 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 auratus. 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 (m. 1) 

 manifests its true niolar 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 



1 _ 1 



33 

 33 



canines 



q _ q 



_ 



molars <r^> 28. If the first per- 



manent premolar has any predecessor, it 

 must be rudimental and disappear early in 



