Bonellia viridis

Bonellia viridis appears in The Second Sex as a biological example that complicates any simple division between male and female: its embryo is initially asexual, and its eventual sexual development depends on the uncertainties of development. The example supports the book’s account of sexual differentiation as a process, not an absolute boundary present from the outset.

Biological Example

The discussion places Bonellia viridis among animals for which sexual differentiation is not fixed at the beginning of embryonic development. Its embryo is first asexual; what sex it eventually develops is described as depending on the uncertainties of its development. The example is introduced alongside broader observations that, in some plants and primitive animals, individuals may produce both ova and sperm, and that even after sexes separate, the distinction between them is not as absolute as the boundaries between species.

Role in the Argument

Bonellia viridis helps establish a distinction between sexual differentiation and the claim that biological categories are immutable from the start. The book describes males and females as developing as variations on a common base, with an initially undifferentiated tissue later developing into reproductive organs. This example does not by itself establish a social theory; rather, it contributes to the biological discussion by showing that sex differentiation can emerge during development and that biological variation includes intermediate forms.