Embryogenesis is inherently a process that unfolds through time. Every part of a living embryo is constantly in flux, making it challenging to describe them at any given point. To make sense of development, embryologists have used drawings and micrographs to create series of developmental stages. These staging systems are used to temporally orient specimens and as resources for communities of researchers investigating the same species. Often referred to as “normal stages,” these visual series are also used as standards of normal development against which the results of experiments can be compared.