pinnipeds, sirenians, otters, and bears have differentiated teeth represented in a formula in which numbers indicate the quantity of each type of tooth in the upper and lower jaw. The formulas presented in this guide take the following form: IncisorsÊ(I) upper/lower, caninesÊ(C) upper/lower, post-caninesÊ(PC) upper/lower. In otters, bears, and some sirenians, the post-canines are differentiated into premolarsÊ(PM) and molarsÊ(M). The numbers refer to the number of teeth on each side of the jaw.