doliolaria larva
From ZooTerms (Dictionary of Invertebrate Zoology)
doliolaria larva also pentacrinoid: (Echinodermata: Crinoidea) A free-swimming bilaterally symmetrical larva of the crinoids and a post auricularia holothurian larva; characterized by possessing a large apical tuft and several (4 or 5) ciliated bands around the body; dipluerula.
