340 
LIFE, IN ITS HIGHER FORMS. 
greatest of quadrupeds — between the Mouse and the Ele- 
phant. Not to speak of the similarity in form of many of 
their bones, and their jaws formed of parallel laminae, the 
latter is, like the former, destitute of canines, while its 
incisors assume a curved direction, aud project from die 
mouth as great tusks. The molars of the Elephant, like 
those of the Guinea-pig, are composed of a number of ver- 
tical transverse lamina; of bone, each covered with enamel, 
cemented together by a third substance closely similar to 
ivory. “ This last substance, being much softer than the 
enamel, wears away faster by the masticatiou of the food, 
so that the enamel remains considerably higher, and, in 
this manner, the surface of each grinder acquires a ribbed 
appearance, as if originally formed with ridges. From 
very accurate observations which have been mode on the 
Asiatic Elephant, it appears that the first set of grinders, 
or milk-teeth, begin to cut the jaw eight or ten days after 
birth, and the grinders of the upper jaw appear before 
those of the lower one. These milk-grinders aro not shed, 
but are gradually worn away during the time the second 
set arc coming forward, and, as soon as the body of the 
grinder is nearly worn away, the' fangs begin to be ab- 
sorbed. From the end of the second to the beginning of 
the sixth year, the third set come gradually forward as the 
jaw lengthens, not only to fill up this additional space, but 
also to supply the place of the second set, which are during 
the same period gradually worn away, and have their 
fangs absorbed. From the beginning of the sixth to the 
end of the ninth year, the fourth set of grinders come for- 
ward, to supply the gradual waste of the third set. In 
this manner, to the end of life, the Elephant obtains a set 
