254 



THE DENTAL SYSTEM OF THE PRIMATES [SECT. A 



ANTHROPOIDEA. Hominidae. Homo sapiens. 



An aboriginal native of Australia (Fig. 188). The upper median incisors 

 are but slightly larger than the lateral incisors ; the crowns are extensive ; of 

 the lower teeth, the lateral pair slightly exceed the median pair in bulk. 



The milk, temporary or deciduous dentition of the Primates comprises a 

 smaller number of teeth than that found in the permanent set. Among the 

 Anthrojxndea, the Platyrrhine and Katarrhine groups are moreover distin- 

 guished by the deciduous dentition as clearly as by the later teeth. Thus in 

 all the Anthropoidea the deciduous dentition includes two incisors and a 

 canine tooth on each side of the jaws, and in the upper and lower jaws alike. 

 To these teeth, three deciduous teeth (" milk-molars ") are to be added in the 

 Platyrrhine division, and they are subsequently replaced by the three dis- 

 tinctive premolars of those animals. The Katarrhine division has but two 

 deciduous molars, i.e. the number here corresponds to that of the permanent 

 teeth which replace them later. The following formulae are employed by 



frt#2). 



Fig. 187. Fig. 188. 



Fig. 187. Incisor teeth of a Chimpanzee (young ? W. L. H. D. priv. coll.). 

 Fig. 188. Incisor teeth of an aboriginal native of Australia. (Mus. Anat. Cant.) 



Professor Bolk 1 for comparing the numbers and the characters of the 

 deciduous and permanent dentitions. The permanent teeth are here dis- 

 tinguished by capital letters : the formulae are accordingly : 



Katarrhinae 2 I 1 C 2 P 



2 i 1 c 2 m 3 M 



Platyrrhinae- 



2 i 1 c 



2 I 1 C 



2 I 1 C 



2 i 1 c 



2 m 



2 P 



2 P 



3 in 



3 M 



3 M 



2 i 1 



2 I 1 



3 m 

 3 P 



3 M 



upper jaw. 

 lower jaw. 



upper jaw. 

 lower jaw. 



1 Koninklijke Akademie run Wetenschappen, 1906, Ap. 26, p. 782. 



2 For the Hapalidae (Marmozets) the Platyrrhine formula must be changed by 



/2M\ 



substituting two permanent molars above and below ( 1TVI ) for the three teeth 



indicated here. 



2M 



