74 Mammalia. Digestive System. 



The Permanent series consists of 



.2.2 1.1 2.2 3.3 



' 2-72' ' rri'^ '^ 27^' ^ 37-3 = ^^- 



The outer Incisor and the two anterior Premolars of the ' typical ' 

 series being suppressed. Number, They are the same in number 

 and in kind as in the Catarrhine Quadrumana. Situation. They 

 stand in one continuous unbroken row, describing a regular parabolic 

 curve, and seldom have any, even the slightest, interval or 'diastema* 

 between the lateral Incisor and Canine on either side of the upper 

 jaw. The Incisors are vertical, or nearly vertical, in position, 

 Form. They are of equal length or depth of crown, and show no 

 sexual distinctions. The Incisors are characterised by their truo 

 wedge-like form, equality of sizt), and small size relatively to the 

 other teeth and to the entire skull. Both upper and lower Pre- 

 molars are bicuspid and implanted by a single conical fang (or, two 

 conate, in upper jaw) : the outer curve of the premolar part of 

 the dental series being greater than the inner one, the outer cusp of 

 each Premolar is the larger. The third Molar (dens sapientice) is the 

 smallest in both jaws. In the Upper Jaw the first and second true 

 Molars support four trihedral cusps which present strong sigmoid 

 curves, and are generally implanted by three diverging fangs ; the 

 first Molar is considerably worn before the completion of the Molar 

 series by the acquisition of the Bens Sapientiae. In the Lower Jaw 

 the crowns of the true Molars are quinque-cuipid, and these teeth 

 are implanted by two fangs with median grooves. 



2 2 



Quadrumana. Numler. The Incisors are commonly and 



(3 . 3\ ' 



r- 5 I. Situation. The Incisors generally 



incline forward from the vertical line*. A break or diastema* in the 

 dental series is generally found for the reception of the crowns of 

 the Canines when the mouth is closed. The Canines and Premolars 

 generally form nearly a straight* line with the Molars. Form. The 

 lower Incisors are broad and thick. The Premolars, which are 

 bicuspid, have the outer cusp of the first and the inner* cusp of the 

 second the largest ; alternating thus by reason of the teeth being 

 situated in a straight line. The Molars are broad and tuberculated, 

 and the four cusps rise distinct and independently of each other. 



Catarrhina. Structure. All the teeth are simplices ; the coronal cement is 



2 2 



thin. Kumher. Haye the same number and kind of teeth as Bimana : m '- 



^ 2.2 



Cf. Bimana, supra. 



