905 



number of " formed and forming " teeth in the jaws at such period, commonly from seven to 

 eight years of age, is 48 : viz. 20 deciduous teeth, 20 permanent successors, and 8 superadded 

 true molars. 



5865. (Slide, Div. 10.) " The teeth from one side of both jaws of a Youth about 

 eleven or twelve years old, showing the further progress of the one set towards 

 perfection, and of the other towards decay." 



The deciduous incisors and canines have been shed, and the permanent ones have cut the 

 gum. The fang of the canine is not yet complete. The second incisors have not been pre- 

 served in this series. The first upper premolar has come into place and has pushed out its 

 predecessor : the first lower milk-molar and the second in both jaws remain, with their fangs 

 much absorbed. Only the base of the fangs of the premolars is formed : the first true molars 

 have the fangs nearly complete : the enamel seems to have been dissolved away from the 

 summit of the crown by an acid. The crown of the second true molar is complete : that of 

 the third, or ' dens sapientiae,' is only beginning to be calcified. The above teeth form the 

 subjects of fig. 2. pi. xi. Op. cit. 



5866. (Slide, Div. 11.) The teeth from one side of both jaws of a Youth about 

 fourteen years of age. 



The permanent incisors and canines are in place ; but the deciduous molars have not been 

 shed : their fangs are much absorbed and those of their successors are half-formed ; the fangs 

 of the second true molar are in a similar state, and the crown of the third true molar is 

 more advanced, especially in the upper jaw. 



5867. (Slide, Div. 12.) The teeth from one side of both jaws of a Youth about 

 eighteen years of age. 



The premolars or bicuspids are complete and have pushed out the milk-molars, all the 

 deciduous series being now shed. The fangs of the second true molar are complete in the 

 lower jaw, but not in the upper jaw. The third true molar shows a corresponding advance 

 of development in the lower jaw. 



5868. (Slide, Div. 13.) The calcified summits of the crowns of the deciduous teeth, 

 viz. two incisors, canine, and two molars, " from one side of both jaws, of a 

 Foetus of seven or eight months, showing the progress of ossification : " this is 

 greatest in the first incisor and decreases to the last molar. 



The specimens are the subjects of fig. 4. pi. ix. Op. cit. 



5z 



