Fig. 18From: Insights into the structure and morphogenesis of the giant basal spicule of the glass sponge Monorhaphis chuniA model of spicule growth at the apical tip proposed by Wang [28, 29], modified (left) and as revealed by the present study (right). a Stage when spicule is still growing. b Final stage when growth is arrested. Red–AF, yellow–C, green–layered PG silicaBack to article page