schis·to·som·u·lum 
(shĭs′tə-sŏmyə-ləm)
(shĭs′tə-sŏmyə-ləm)n. pl. schis·to·som·u·la (-lə)
The immature form of a parasitic schistosome after it has entered the blood vessels of its host.
[New Latin schistosōmulum, from diminutive of Schistosōma, genus name; see SCHISTOSOME.]