Trachymedusae :: Trachymedusae (n. pl.) A division of acalephs in which the development is direct from the eggs, without a hydroid stage. Some of the species are parasitic on other medusae..
Trachystomata :: Trachystomata (n. pl.) An order of tailed aquatic amphibians, including Siren and Pseudobranchus. They have anterior legs only, are eel-like in form, and have no teeth except a small patch on the palate. The external gills are persistent through life..
Trachyte :: Trachyte (n.) An igneous rock, usually light gray in color and breaking with a rough surface. It consists chiefly of orthoclase feldspar with sometimes hornblende and mica..
Trachytic :: Trachytic (a.) Of, pertaining to, or resembling, trachyte..
Trachytoid :: Trachytoid (a.) Resembling trachyte; -- used to define the structure of certain rocks.