Fig. 1. Cross-section of the outer epaxial musculature of a 2 d.p.h. larval haddock incubated at 6°C, stained with Paragon, demonstrating distinctive cellular and structural features. Bar, 20 µm. spF, superficial myofibres; dF, deep myofibres; ssPZ, superficial-deep septum proliferation zone; mt, mitochondria; white arrowheads, small new myofibres. For descriptive purposes, the inset (50% size of the main figure) illustrates the outlines of individual myofibres.