Foetal lens development. Light micrograph of a section through the lens in the developing eye of a foetus. In this fetal eye the developing lens shows clearly how its lens fibres are produced. At centre right a row of epithelial cell nuclei is seen, which near the equatorial poles, turn inwards to form a crescent shape. This represents the addition of new, elongating lens cells (or fibres) to the equator thereby adding, one by one, successive fibres from inwards to outwards in direction. Simultaneously the lens cells will lose their nuclei, become lens fibres' and synthesise and store special proteins which permit the passage of light. New epithelial lens cells are produced throughout life. Magnification: x56, when printed 10 centimetres