The medusa of Turritopsis dohrnii is bell - shaped , with a maximum diameter of about 4.5 millimetres ( 0.18 in ) .
Is about as tall as Turritopsis dohrnii is wide .
The medusa of Turritopsis dohrnii is bell - shaped , with a maximum diameter of about 4.5 millimetres ( 0.18 in ) and is about as tall as it is wide .