TEETH OF DIPHYODONTS. 331 



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 quadrupeds 

 subsisting principally on fish ; the opposite or obtuse, thick form 

 of the premolars is manifested by some of the Musangs, e.g. 

 Paradoxurus auratus. The deciduous dentition consists, in the 

 Viverrine family, of — 



.3.3 1.1 3.3 M 

 2 3.3 ;C n ;m 3T3 =28 - 



The interlocking of the crowns of the teeth of the upper and 

 lower jaws, which is their general relative position in the Carni- 

 vora, is well-marked in regard to the premolars of the Viverridoe ; 

 as the lower canine is in front of the upper, so the first lower pre- 

 molar 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 and the sectorial tooth, 

 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 Carnivora to form the lower sectorial, 

 sends the three tubercles of its anterior part to fill the space 

 between the sectorial and the first true molar above. In the 

 Musangs, 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 e Palm-cats.' 



The normal dental formula of the genus Canis is — 



33 11 4 4 2 2 

 ^ ;C LT^4i4 ;m 3i3 = 42(fig - 293 ' III -> 



The incisors increase in size from the first to the third; the 

 trenchant margin of the crown is divided by two notches into a 

 large middle and two small lateral lobes. The canines, c } are 

 curved, sub-compressed ; the enamelled pointed crown forms nearly 

 half the length of the tooth, and is smooth, without any groove. 

 The premolars, fig. 293, p 1-4, have strong sub-compressed conical 

 crowns gradually enlarging from the first to the third, p 3, in the 

 upper jaw, and to the fourth, p 4, in the lower jaw, and acquiring 

 one or two accessory posterior tubercles as they increase in size. 

 The fourth upper premolar, p 4, presents a sudden increase of 



