Sentence:  The copepod <WSD>nauplii</WSD> concentrations were significantly different among stations and by depth (Appendices 3 and 4). 
Meaning of the word marked with <WSD> tags:  A crustacean larva that has three pairs of locomotive organs (corresponding to antennules, antennae, and mandibles), a median eye, and little or no segmentation of the body. (from mid 19th c.)