Remarks on the anatomy and ontogeny of scales of teleosts. I

Densitometer records were made from the scales of a number of fish species, mainly from pikeperch. Analysis of the records showed that the pattern of hollows, representing the circuli in the curves, was very regular. No arrangement into groups of narrowly interspaced circuli could be demonstrated. It was therefore concluded that the circuli of the surface layer do not produce the “growth-checks”. Ringlike structures were also present in the fibrous basal plate. These were about 3–5 μm closer together than the circuli. These two circular gratings of slightly different inter-ring spacing will create an interference pattern, in this case a circular moiré pattern, having no direct relation to the structures present in the two layers forming the scale.