Fig. 1From: Anatomy and the type concept in biology show that ontologies must be adapted to the diagnostic needs of researchContinuity between microvilli (evaginations) and crypts (invaginations) and examples from different tissues. A Scheme of the continuum between microvilli and crypts (modified from [50]). B Microvilli of the gut epithelium in Artemia salina (Crustacea), metanauplius. C Epidermal microvilli in Owenia fusiformis (Annelida). D Microvilli in a developing rhabdomeric photoreceptor cell in Achelia brevicauda (Pantopoda). E Microvilli of a chaetoblast during chaetogenesis in Johnstonia clymenoides (Annelida). F Stereovilli of a chaetoblast during chaetogenesis in Echiurus echiurus (Annelida). G Duct of the antennal nephridium in Artemia salina (Crustacea). Arrows mark basal invaginations of the cell membrane. H Basal crypts of gut cells in Artemia salina (Crustacea)Back to article page