228 PROBOSCIDIA. 
together, prior to their basal confluence, by the external 
cement ; this substance is generally more or less decom- 
posed in fossil grinders, and the parts of the complex tooth 
then become detached: a separate plate, with its digital 
processes, offers a rude resemblance to a hand, and such 
specimens have been figured by the older collectors of 
petrifactions, under the name of ‘“ Cheirolites,” as the 
fossilized hand of a monkey ora child. The digital pro- 
cesses of the last formed plates of the large molar tooth m 
fig. 90, are shown at f, f, f: this figure well illustrates 
the progressive development of the Elephant’s tooth from 
before backwards ; the formation begins with the summits 
of the anterior plate, and the rest are completed in succes- 
sion: the tooth is gradually advanced in position as the 
growth proceeds, and its anterior plates are brought into 
use before the posterior ones are formed. When it cuts 
the gum, the cement is first rubbed off the digital summits ; 
then their enamelled cap is worn away and the central den- 
tine exposed ; next, the digital processes are ground down to 
their common uniting base and a transverse tract of dentine 
—now the upper margin of the plate—with its border of 
enamel is exposed ; finally, the transverse plates themselves 
are abraded to their common base of dentine, and a smooth 
and polished tract of that substance of greater or less ex- 
tent is produced. When the tooth has been thus reduced 
to an uniform surface it becomes useless as an instrument 
for grinding the coarse vegetable substances on which the 
Klephant subsists, and is shed. 
The tooth figured (90) exhibits all the foregoing stages of 
attrition: the common longitudinal base of dentine is ex- 
posed at d’; the continuous margin of a transverse plate at 
d: and the digital summits of varying breadth, according 
to the degree of abrasion, appear behind, and are followed 
