Fig. 3. Cross-section of the dorsal epaxial musculature at the level of the posterior gut of a 28 d.p.h. larval haddock incubated at 6°C, stained with Paragon, illustrating distinctive myotomal features about the horizontal myotome. Bar, 30 µm. spF, superficial myofibres; dF, deep myofibres; sPZ, superficial proliferation zone; ssPZ, superficial-deep septum proliferation zone; hmy, horizontal myoseptum; Lln, lateral line nerve.