Fig. 18. Schematic diagrams showing the arrangement of microtubules with respect to
the margins of cells (broken lines) and the apparent locations of the proximal ends of
micro tubules with respect to centrosomes. Centrosomes are represented by a pair of black
rectangles (centrioles) surrounded by stippling (pericentriolar material). A. An osteoblast
near the central portion of aHyphessobrycon scale. B. An osteoblast near the anterior edge
of a Hyphessobrycon or Brachydanio scale where circuli are most closely spaced. C. A
fibroblast of a Hyphessobrycon or Brachydanio scale.