NOTATION AND SYMBOLS OF TEETH. 313 



by tills character of its development, a true molar, and 

 the germs of the permanent teeth, which are exposed in 

 the substance of the jaw, between the diverging fangs of 

 the molars d 3 and d 4, prove those molars to be tempo- 

 rary, destined to be replaced, and prove also that the teeth 

 about to displace them are premolars. According, there- 

 fore, to the rule previously laid down, we count the per- 

 manent molar in place as the first of its series, m 1, and 

 the adjoining premolar as the last of its series, and con- 

 sequently the fourth of the typical dentition, or p 4. 



We are thus enabled, with the same scientific certainty 

 as that whereby we recognize in the middle toe of the 

 foot the homologue of that great digit which forms the 

 whole foot and is incased by 1^e hoof of the horse, to 

 point to 2^ 4, or the second bicuspid in the upper jaw, and 

 to m 1, or tha first molar in the lower jaw, of man, as the 

 homologues of the great carnassial, or flesh-cutting teeth 

 of the lion (Fig. 69). We also conclude that the teeth 

 which are wanting in man to complete the typical molar 

 series are the first and second premolars, the homologues 

 of those marked p 1 and ^ 2 in the hog. The character- 

 istic shortening of the maxillary bones required this dimi- 

 nution of the number of their teeth, as well as their size, 

 and of the canines more especially; and the still greater 

 curtailment of the premaxillary bone is attended with a 

 diminished number and an altered position of the incisors. 



The homologous teeth being thus determinable, they 

 may be severally signified by a symbol as well as by a 

 name. The incisors, e. g.^ are here represented by their 

 initial letter, z, and individually by an added number, il, 

 i 2, and i 3 ; the canines by the letter c; the premolars by 

 the letter p) ; and the molars by the letter m; these also 

 being differentiated by added numerals. Thus the num- 

 27 



