About Arachnoides placenta (Linnaeus, 1758)
Arachnoides placenta is a species of sea urchin that belongs to the family Clypeasteridae and the genus Arachnoides. Like other sea urchins, individuals of this species have an armour-like exoskeleton covered in spines, and they live in marine environments. This species was first formally described scientifically by Carl Linnaeus in 1758.