T.
Tentacula, the feelers of snails which inhabit shells.
Tesselated, checkered like a chessboard.
Testacea, the third order of worms, including those which are covered with a testaceous shell.
Testaceous, consisting of carbonate of lime and animal matter.
Tetragonal, four cornered.
Torose, swelling into knobs or protuberances.
Tortuosity, wreath, flexure.
Tortuous, twisted, wreathed, winding.
Transverse, placed across or crossways. When the breadth of a shell is greater than its length, it is called transverse.