Figure 3

Object colour solids of juvenile and adult lungfish. The volume of the object colour solid was calculated for juvenile (A, B) and adult (C, D) lungfish, both with (A, C) and without (B, D) the filtering effects of the yellow ellipsoidal and red oil droplet spectral filters in the MWS and LWS cones. The tetrachromatic colour space of the juvenile lungfish (A, B) is shown by two different projections of the spaces defined by the quantum catches of the UVS, SWS and MWS cones and also the SWS, MWS and LWS cones. Note the increase in the volume of the object-colour solid (and consequently the number of discriminable colours) in both juveniles (B) and adults (D) with spectral filters, relative to the situation without the effects of spectral filters. See Fig. 2 for explanation of abbreviations. Projections were generated using Mathematica software (Wolfram Research, Inc., Champaign, IL, USA).