Magnesium distribution in avian eggshells

Abstract

1. 1. There were two peaks in the concentration of Mg 2+ in the eggshells of 10 species of Galliformes, one in the cone layer and the other at the outer edge of the shell; there was only one peak (in the cone layer) in those of more than 60 species of 19 other orders of birds. 2. 2. The width of the zone of the Mg 2+-rich inner layer was about 50% of the total shell width in small but only 10% or less in large eggs.