part of part of embryonic structure post-anal tail bud Kupffer's vesicle ZFA:0000001 This class was sourced from an external ontology (teleost_anatomy). Its definitions, naming conventions and relationships may need to be checked for compatibility with uberon Small but distinctive epithelial sac containing fluid, located midventrally posterior to the yolk cell or its extension, and transiently present during most of the segmentation period. Kimmel et al, 1995. Kupffer's vesicle has been compared to the mouse embryonic node. Drummond et al, 2005. UBERON:2000001