Post-hatching growth and allometry of the teleost brain.

The growth of the brain in the rainbow trout follows an S curve: E = 0.04 t3 + 0.26 t2 - 0.06 t + 0.04 with t (time) in days and E (brain weight) in mg. The growth of the brain, relative to the body, can be given, after longarithmic transformation, by: Y = 0.011 + 0.835 X - 0.047 X2 where Y is log brain weight and X log body weight. This formula is consistent with that of every species after necessary changes of origin. The coefficients of allometry corresponding to this curve vary from 0.788 (body weight from 0.01 to 0.1 g) to 0.226 (body weight from 10 to 100 kg), the most common values varying between 0.507 (body weight from 10 to 100 g) and 0.414 (body weight from 100 g to 1 kg).