That crescent is the lunula. We don’t all have them (so don’t panic if you don’t!). The Oxford English Dictionary (OED) carries a September 1891 listing from the British Medical Journal ...

P. lunula cannot use that same strategy: it has chloroplasts organized in the form of a complex network, necessitating a different form of motion to avoid bright light.

It is used to treat mild to moderate fungal nail infections that does not involve the lunula, by painting it onto the infected fingernails or toenails. The lunula is the crescent-shaped area ...

The unexpected solution has been found by researchers at the University of Amsterdam. Pyrocystis lunula is the full scientific name. Sailors and fishermen are well aware of the effects of P.