Diatoms are a major group of algae. A characteristic feature of diatom cells is that they are encased within a cell wall made of silica (hydrated silicon dioxide) called a frustule.
The Astounding And Horrific World As Seen Under A Microscope
Amazing! Colorized scanning electron micrograph of malaria (Plasmodium yoelii nigeriensis) oocysts ( thick-walled structure in which sporozoan zygotes develop) developing on the midgut wall of the mosquito Anopheles. Credit: Hilary Hurd, Wellcome Images
Staphylococcus saprophyticus scanning electron micrograph › Micronaut: The fine art of microscopy by science photographer Martin Oeggerli
Luxology Gallery: The life cycle of "Babesia microti" | Babesia is a malaria-like parasite, also called a “piroplasm,” that infects red blood cells.
"Eyelash mite. Coloured scanning electron micrograph (SEM) of an eyelash, or follicle, mite (Demodex folliculorum), a harmless parasite which lives inside human hair follicles." - eeew