planula
UK /ˈplæn.jʊ.lə/ · US /ˈplæn.jə.lə/ noun
Forms planulae
- noun (biology) In embryonic development, a vesicle filled with fluid, formed from the morula by the divergence of its cells in such a manner as to give rise to a central space, around which the cells arrange themselves as an envelope; an embryonic form intermediate between the morula and gastrula.
- noun (zoology) The larva of a hydrozoan, which is free-swimming and covered in cilia.
Etymology
Borrowed from Latin plānula, diminutive of plāna (“plane”).
Webster’s 1913
- noun In embryonic development, a vesicle filled with fluid, formed from the morula by the divergence of its cells in such a manner as to give rise to a central space, around which the cells arrange themselves as an envelope; an embryonic form intermediate between the morula and gastrula. Sometimes used as synonymous with gastrula.
- noun The very young, free-swimming larva of the coelenterates. It usually has a flattened oval or oblong form, and is entirely covered with cilia.
Etymology [L., a little plane.]
Sources: Wiktionary · Webster’s 1913 — from the Wiktionary entry “planula”, CC BY-SA 4.0. Details