Chapter 3 - Section 3.4 - Figure 3.33 - Centrioles - Page 107: 1

Fig. 3.33 A centriole is a cylinder composed of nine groups of microtubule.

There are three microtubule in each of these nine groups. In contrast in an axoneme there are only two microtubules in each group( also nine groups). In addition, an axoneme has a central pair of microtubules which are absent from centrioles.