Portions of Brachydanio skin and its scales were prepared for electron microscopy using
procedures outlined elsewhere (Dane & Tucker, 1985) except that scales were fixed using the
Supracellular microtubule alignments 275
method described by Baird et al. (1967) and then decalcified for 72 h (Waterman, 1970) prior to
dehydration. In addition, each portion of skin and its scales was sandwiched within a strip
(3 cmXO-75 cm) of copper gauze (0 -4mm mesh-spacing) that was folded around it before fixation
and remained until dehydration was completed. This was to prevent the marked curling up of skin
portions, which otherwise occurs during fixation.