- taxon
- teleost
- temperate waters
- temperature
- temporal region
- temporooccipital
- tentacle
- tenuate
- terrestrial
- territorial
- testes
- TFRI
- thermocline
- thermophile
- thorax
- thorn
- throat
- tidal
- tongue
- tooth
- transition
- transverse
- tricuspidate
- tridentate
- trilinearis
- tropical
- truncate
- trunk
- tubercles
- tubicolous worms
- tubular
- type