- tadpole larva
- tagma
- tail
- tailfan
- teleoconch
- telotroch
- telson
- tentacle
- tentacle bulb
- tentaculae
- tentacular cirri
- tentacular club
- tentacular membrane
- tentilla
- tergite
- tergum
- terminal claw
- test
- testis
- thelycum
- thorax
- thrust block
- tooth list
- toothlet
- tornaria
- translucent
- tricuspoid
- trochophora
- trochophore
- trophozooid
- truncate
- trunk
- tubercle