TEETH OF DIPHYODONTS. 



319 



crown is deeper, the posterior groove is eon tinned lower down 

 upon the fang, and the ridge between the two grooves is more 

 prominent than in the Troglodytes niger. Both premolars, 



Dentition of upper jaw, male TrogUxlyle* QurUla, nat. size, ctu'. 



fig. 255, p 3, and p 4, are bicuspid ; the outer cusp of the first, 

 and the inner cusp of the second being the largest, and the first 

 premolar, p 3, consequently appearing the largest on an external 

 view. The difference is well marked in the female, fig. 254, p 3. 

 The anterior external angle of the first premolar is not produced 

 as in the Orang, which in this respect makes a marked approach 

 to the lower Quadrumana. In Man, where the outer curve of 

 the premolar part of the dental series is greater than the inner 



