part of overlaps develops from start stage end stage lateral ethmoid ZFA:0000226 Large, paired cartilage bones separating the olfactory region from the orbit. Arises from both perichondral and endochondral ossifications (Harrington 1955). Bordered by the mesethmoid anteriorly and overlain by the frontal dorsally, each lateral ethmoid extends medially to meet its fellow posteriorly along the midline. Develops from the laminae orbitonasales. TAO:0000226 zebrafish_anatomy lateral ethmoids olfactory region chondrocranium lamina orbitonasalis neurocranium endochondral bone autopalatine-lateral ethmoid joint larval:days 14-20 adult