protostome
/ˈprəʊtə(ʊ)stəʊm
/noun Zoology
A multicellular organism whose mouth develops from a primary embryonic opening, such as an annelid, mollusc, or arthropod.These animals are all protostomes - the mouth develops before the anus in the young embryo - and they have long been recognized as belonging together as a group....
- In the complementary category, the protostomes, which includes annelids and arthropods, the blastopore develops into the mouth.
- Arthropods are bilaterally symmetrical protostomes with strongly segmented bodies.
Origin
1950s: from proto- 'primitive' + Greek stoma 'mouth'.
- negative buoyancy
- negative buoyant
- negative capability
- negative catalysis
- negative catalyst
- negative confession
- negative crystal
- negative definite
- negative energy
- negative equity
- negative eugenics
- negative evidence
- negative eyepiece
- negative feedback
- negative flag
- negative g
- negative gearing
- negative geotropism
- negative glow
- negative-going
- negative growth
- negative income tax
- negative instance
- negatively
- negativeness