Fig. 2. Changes in (A) total protein and (B) the amount of alanine in the free amino acid pool during development and growth of the sea urchin Lytechinus pictus. Embryos, open circles; unfed larvae, open squares; fed larvae, filled squares. Values are means ± s.e.m., and where not shown errors fell within the graphical representation of the data point. (A) Changes in total protein content. Each data point is the mean value of 2-3 determinations. The fitted line shows an increase in protein content for fed larvae: y=20.68e^0.17x (r²=0.99). (B) Changes in the amount of alanine in the free amino acid pool. Each data point is the mean of 6 measurements. The fitted line shows an increase in alanine in fed larvae: y=2.460e^0.19x (r²=0.99).