Furthermore, in some Hyphessobrycon osteoblasts that are
associated with circuli it is evident that individual microtubules (or small groups of
microtubules) curve fairly abruptly through about 90° out of alignment with circuli
at many points along the anterior margin of an osteoblast (Fig. 15). The portions of
microtubules oriented at right angles to circuli are thus likely to be the distal portions
of the microtubules that are aligned with circuli and are closest to the anteriorly