Sentence:  The primary locomotory muscles of terrestrial mammals are <WSD>appendicular</WSD>, so much of the locomotory heat energy of the muscle is transferred to the environment rather than directed into the body cavities; this is not the case for ascrotal marine mammals, whose primary locomotory muscles surround the abdominal and pelvic cavities. 
Meaning of the word marked with <WSD> tags:  Of or pertaining to a limb or appendage.