Note 15 — DESCRIPTION OF FRAGMENTS OF A LOWER JAW AND TEETH OF A TOXODON.
Reading edition
Besides the relation to food requiring much comminution, which teeth with persistent pulps bear, they are also connected with the longevity of the individual. The term of life in a herbivorous animal, with grinders of temporary growth, is, of necessity, dependent on the duration of these essential aids to nutrition; thus, a sheep generally wears down its grinders in twelve years, and its natural term of life is consequently limited to about that period.