Sentence:  Japanese fishermen have sometimes observed that sardines hauled up in their nets during a tsunami have enormously swollen <WSD>stomachs</WSD> ; the fish have swallowed vast numbers of bottom living diatoms , raised to the surface by the disturbance . 
Meaning of the word marked with <WSD> tags:  an enlarged and muscular saclike organ of the alimentary canal; the principal organ of digestion