314 NOTATION AND SYMBOLS OF TEETH. 



ber of these teeth, on each side of both jaws, in any given 

 species — man, e.g. — may be expressed by the following 



brief formula: i- — -, c ~.p .m =32; and the 



2—2' 1—1' ^2— 2' 3—3 



homologies of the typical formula may be signified by i 1, 



z 2 ; c; j9 3, ^j 4 ; m 1, m 2, m 3 ; the suppressed teeth being 



z3, ^9 1, and^:>2. 



These symbols, it is hoped, are so plain and simple as 

 to have formed no obstacle to the full and easy compre- 

 hension of the facts explained by means of them. If 

 these facts, in the manifold diversities of mammalian 

 dentition, were to be described in the ordinary way, by 

 means of verbal phrases or definitions of the teeth — e. g. 

 " the second deciduous molar, representing the fourth in 

 the typical dentition," instead of d 4, and so on — the de- 

 scription would occupy much space, and would levy such 

 a tax upon the attention and memory as must tend to 

 enfeeble the judgment, and impair the power of seizing 

 and appreciating the results of the comparisons. 



Each year's experience strengthens my conviction that 

 the rapid and successful progress of the knowledge of 

 animal structures, and of the generalization deducible 

 therefrom, will be mainly influenced by th6 determina- 

 tion of the nature or homology of the parts, and by the 

 concomitant power of condensing the propositions relating 

 to them, and of attaching to them signs or symbols equiva- 

 lent to their single substantive names. In my work on 

 the Archetype of the Skeleton^ I have denoted most of the 

 bones by simple numerals, which, if generally adopted, 

 might take the place of names; and all the propositions 

 respecting the centrum of the occipital vertebra might be 

 predicated of the figure "1" as intelligibly as of "basi- 

 occipital." 



