Table 1.

Glossary of technical terminology

Phylogenetic terms	Developmental types	Larval types
	(see also Figure 2)
clade (monophyletic group) - an ancestor and all its living and extinct descendents	direct development - development without a larval stage	gastrula - hypothetic ancestor (gastraea) and early developmental stage of many neuralians, consisting of ecto- and endoderm
apomorphy (advanced character) - a new character (state) at a node on the phylogenetic tree	indirect development (also called biphasic life cycle, including pelago-benthic life cycle) - development with a larval stage	ephyra - newly strobilated scyphozoan medusa
		trochaea - hypothetic protostomian ancestor, a gastrula with an archaeotroch, i.e., a peri-blastoporal ring of compound cilia (see Figure 11)
		trochophora - typical larva of spiralians with downstream-collecting ciliary bands (see Figures 5 and 6)
plesiomorphy (primitive character) - a character (state) inherited from an earlier node on the tree	lecithotrophic - larva nourished exclusively by yolk
		cyphonautes - planktotrophic larva of bryozoans with ciliary sieving
	planktotrophic - larva feeding in the plankton	actinotrocha - larva of phoronids with tentacles with ciliary sieving
	facultative feeding – larva which may feed in the plankton, but which can develop normally without feeding	dipleurula - typical larva of ambulacrarians with perioral band of single cilia with upstream-collecting by ciliary reversal; the larvae of the echinoderm classes have special names (see Figure 9)
homoplasy (convergence) - apparently similar structures evolved independently in different clades
	poecilogony - various developmental types in the same species	tornaria - dipleurula larva of enteropneusts with a perianal band of compound cilia used in swimming (see Figure 9)