Original Cards to Determine Type of Mottling on Terns' Eggs <p>Consists of :</p> <li>three cards with eggs showing fine markings and coarse markings used to determine mottling and colour</li> <li>individual drawings of terns' eggs showing various mottling </li> <li>information about mottling scale</li> <li>one watercolour of tern egg</li> 1920