Fig. 11. Double-label immunohistochemistry using -tubulin (green) and FMRFamide (red) antibodies. In A, a dual filter shows the two colours together. The small arrows indicate FMRFamide cell bodies and neurites, and the large arrows indicate some of the tubulin-stained cell bodies. B and C are from identical areas (no change in focus) with a change from a FITC filter (B) to a TRITC filter (C). Note the neuron indicated by the arrow in B is not present in C indicating it was immunoreactive to the tubulin antibody, but not to FMRFamide antibody. This suggests the presence of two distinct neuronal types in the subumbrellar segments of Aequorea.