442 QUADRUMANES, 



molars, has no deciduous predecessor. (1) In the true Monkeys 

 (Cercopitheci), the Gibbons, and the Orangs, the last molar of the 

 lower jaw has a square quadri-tuberculate crown like that above. 



The incisors have always a shape conformable to their name, 

 but are very strong and thick ; in the upper jaw the middle are larger 

 than the lateral ones, and both are larger than those below. In the 

 Baboons, the Monkeys, and the Semnopitheques, the lower incisors 

 (PI. 116, fig. 2, i) are sub-equal, or the middle ones are larger 

 than the lateral ones in the Gibbons (ib. fig. 6), and the Orangs, 

 (PL 117, PL 119, fig. 1), the middle lower incisors are the smallest, 

 as in Man. The lateral inferior incisors of the Baboons (PL 116, 

 fig. 4*, i) and Semnopitheques (ib. fig. 5)are further distinguished by 

 the oblique truncation of the outer angle of the crown. Both series 

 of incisors describe a deeper curve in the Baboons and Monkeys 

 than in the Orangs, in which they approach the rectilinear ar- 

 rangement which characterize these teeth in the Human subject. 



The canines are conical, pointed, with trenchant posterior margins, 

 always longer than the adjoining teeth, and acquiring in the males 

 of the great Baboons and Orangs, the proportions of those teeth 

 in the true Garni vora. The Mandrills, {Cynocephalus maimon,) have 

 these dental weapons most formidable for their size and shape ; 

 especially the upper pair, which descend behind the crowns of the 

 lower incisors, and along the outside of the first lower premolars, 

 (PL 116, fig. 4*, p) the crowns of which seem as if bent back by the 

 action of the upper canines : the anterior longitudinal groove of these 

 canines (ib. fig. 4) is very deep, their posterior margin very sharp. 

 A long diastema divides the upper canine from the incisors, a short 

 one separates it from the premolars : these and the three true molars 

 are arranged in a straight line. Each premolar supports a large ex- 

 ternal and a small internal cusp ; the true molars have four pro- 

 minent, sharp-pointed cusps, with an anterior and posterior basal 

 ridge ; they progressively increase in size from the first to the 

 third in all the Baboons. The first premolar of the lower jaw is 



(1) In the private collection of the Baron Van der Capella, near Utrecht, I saw, in the 

 year 1838, a variety in the dentition of an adult Simia Sati/rus, vix: six molar teeth on each 

 side, but only two of these had the characters of premolars. 



