CHAP. VI] THE DENTAL SYSTEM OF THE PRIMATES 265 



sional occurrence of accessory cusps, which have been observed in 

 the Hominidae and in the Gorilla. 



PREMOLAR TEETH. 



Anomalous forms of premolar teeth provide few records. In 

 the Gorilla there is on record one observation (cf. De Terra, op. cit, 

 ]). 256) to shew that the second lower premolar has a tendency to 

 become tricuspid. But the evidence is almost negligible, though 

 it is at least noteworthy that the premolar nearest the molar scries 

 is the tooth concerned. Tricuspid premolar teeth are of common 

 occurrence in the Hominidae, especially in the races (black and 

 yellow) of Oceania (Choquet 1 ). They also characterize certain 

 fossil mammalia, and such premolars have attracted much notice 

 in connection with one of the theories (the "premolar-analogy" 

 theory ) advanced to account for the origin of the molar cusps. 



In the Simiidae the upper premolar teeth have three roots, 

 thus resembling the upper molar teeth in those animals and in 

 the Hominidae. The occurrence of three-rooted upper premolar 

 teeth in the latter (Hominidae) thus demands a special note. 

 The presence of an additional root in these teeth is by no means 

 unknown. The most striking example on record is probably that 

 of the native of Timor (East Indian Archipelago) recorded by 

 De Terra (op. cit., p. 240). In this example the two upper pre- 

 molar teeth of each side were found to possess three roots. Thus 

 the condition normal in the lower Primates was precisely re- 

 produced. 



In dealing with the lower premolar teeth, De Terra (op. cit., 

 p. 241) cites an instance of a lower premolar with two roots, the 

 condition commonly found in the lower Katarrhinae being faith- 

 fully represented in this example. 



MOLAR TEETH. 



Accessory or supernumerary molar cusps are of great interest 

 in relation to the various theories of cusp-development. Such 

 anomalies are therefore discussed in the section (VI) relating to 

 those theories. Here it will suffice to mention that additional 



1 Choquet in L'Odontologie, Jan. -Few 1906, p. 21 of reprint. 



