TEETH 



911 



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 m. 1 and 

 m. 2. 



The first premolar, p. 1, is not developed 

 at any period in the Mangues (Crossarchits), 

 the Suricates (Ryzcena), or the Mangusta 

 paludinosa ; 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. 



The alternate interlocking of the crowns of 

 the teeth of the upper and lower jaws, which is 

 their general relative position in the Carnivora, 

 is well marked in regard to the premolars 

 of the ViverridtB (fig. 580, IV.) : as the lower 

 canine is in front of the upper, so the first 

 lower premolar rises into the space between 

 the upper canine and first upper premolar ; 

 the fourth lower premolar in like manner fills 

 the space between the third upper premolar 

 (/>. 3) and the sectorial tooth (p. 4), playing 

 upon the anterior lobe of the blade of that 

 tooth which indicates by its position, as by 

 its mode of succession, that it is the fourth 

 premolar of the upper jaw. The first true 

 molar below, modified as usual in the Car- 

 nivora to form the lower sectorial, sends the 

 three tubercles of its anterior part to fill the 

 space between the sectorial (p. 4) and the 

 first true molar (m. 1) above. In the Mu- 

 sangs the lower sectorial is in more direct 

 opposition to its true homotype, the first 

 tubercular molar in the upper jaw ; and these 

 Indian Viverridce (Paradoxuri) are the least 

 carnivorous of their family, their chief food 

 consisting of the fruit of palm-trees, whence 

 they have been called " Palm-cats." 



Hyaena. The dentition of this genus pre- 

 sents a nearer approach to the strictly car- 

 nivorous type by the reduction of the tuber- 

 cular molars to a single minute tooth on each 

 side of the upper jaw, the inferior molars 

 being all conical or sectorial teeth : the molar 

 teeth in both jaws are larger and stronger, 

 and the canines smaller in proportion than in 

 the Feline species, from the formula of which 

 the dentition of the hyaena differs numerically 

 only in the retention of an additional pre- 

 molar tooth, p. 1 above and p. 2 below, 

 on each side of both jaws. The dental 



*> f j 



formula of the genus Hyaena is : in. ~ , 



11 



pm. 



44 



11 



33' 

 : = 34. The 



crowns of the incisors form almost a straight 

 tranverse line in both jaws, the exterior 

 ones, above, being much larger than the 

 four middle ones, and extending their long 

 and thick inserted base further back : the 

 crown of the upper and outer incisor (i. 3.) 

 is strong, conical, recurved, like that of a 

 small canine, with an anterior and posterior 

 edge, and a slight ridge along the inner side 

 of the base. The four intermediate small 

 incisors have their crown divided by a trans- 

 verse cleft into a strong anterior, conical lobe, 

 and a posterior ridge, which is notched ver- 

 tically; giving the crown the figure of a 

 trefoil. The lower incisors gradually increase 

 in size from the first to the third ; this and 

 the second have the crown indented ex- 

 ternally ; but they have not the posterior 

 notched ridge like the small upper incisors ; 

 the apex of their conical crown fits into the 

 interspace of the three lobes of the incisor 

 above. The canines have a smooth convex 

 exterior surface, divided by an anterior and 

 posterior edge from a less convex inner side : 

 this surface is almost flat and of less relative 

 extent in the inferior canines. The first 

 premolar above (p. 1) is very small, with a 

 low, thick, conical crown : the second presents 

 a sudden increase of size, and an addition of 

 a posterior and internal basal ridge to the 

 strong cone. The third premolar exhibits 

 the same form on a still larger scale, and is 

 remarkable for its great strength. The pos- 

 terior part of the cone of each of these 

 premolars is traversed by a longitudinal ridge. 

 The fourth premolar is the carnassial tooth, 

 and has its long blade divided by two notches 

 into three lobes, the first a small thick cone, 

 the second a long and compressed cone, the 

 third a horizontal sinuous trenchant plate : a 

 strong triedral tubercle is developed from the 

 inner side of the base of the anterior part of 

 the crown. The single true molar of the 

 upper jaw (m. l) is a tubercular tooth of 

 small size : transversely oblong in the Hycena 

 vulgaris and H.fusca ; smaller and sub-cir- 

 cular in the Hycena crocuta ; still smaller and 

 implanted by a single fang in the Hyosna 

 spel<za : in all the existing species of Hyaena it 

 has two fangs. The first premolar of the lower 

 jaw (p. 2) fits into the interspace between the 

 first and second premolars above, and answers, 

 therefore, to the second lower premolar in 

 the ViverridfB : it is accordingly much larger 

 than the first (p. 1) above ; it has a ridge in 

 the fore-part of its cone, and a broad basal 

 talon behind. The second (p. 3) is the 

 largest of the lower premolars, has an anterior 

 and a posterior basal ridge, with a vertical 

 ridge ascending upon the fore as well as the 

 back part of the strong rounded cone : the 

 third premolar (p. 4.) is proportionally less 

 in the Hyaena crocuta than in the H. vulgaris: 

 its posterior ridge is developed into a sm;^i 

 cone; the last tooth (m. 1) is the sectorial, 



