Fig. 6.

Comparison of the main cell types in the sea cucumber auricularia larva with the sea star bipinnaria and sea urchin pluteus larvae. The cartoons depict the main characterized cell types in echinoderm larvae. Sea cucumber larvae have unique features that distinguish them from other echinoderms, like the presence of hyaline spheres (for lipid storage), one or more short skeletal rods, or ossicles, that do not extend (number varies based on the genus), a single hydrocoel that appears on the left side of the stomach and an extensive neuronal network that do not show long axonal projections towards the internal structures