FishFace

By 79 hpf, the ceratohyal (ch) has increased in size and has straightened its shape from that seen at 55 hpf. It is still difficult to distinguish the dorso-posterior aspect of the ceratohyal from the ventral portion of the articulating interhyal (ih). The separation from the basihyal (bh) dorsally and the contralateral ceratohyal medially at the anterior midline is more distinct from that seen at 55 hpf. Note in the ventral view that the middle region of the ceratohyal now consists of a single-cell layer in the mediolateral dimension, which is consistent with the idea that early cartilage elongation occurs by cell intercalation.