spiculum

Often one single quadriradiate spiculum is distinguished by its extraordinary size.

This surrounds the cloacal outlet, the latter concealing a double spiculum.

The caudal extremity of the male ends in an inverted cup-like pouch, from which the penal spiculum protrudes.

They are called spicula (spiculum, a dart), being often of a pointed form.

The male is supplied with a double spiculum, its tail being always more or less curved towards the central surface.