How many types of nephridia are there? Mention them.

(N/A) Nephridia are of three types:
$(i)$ Pharyngeal nephridia: These are located in segments $4, 5,$ and $6$.
$(ii)$ Integumentary nephridia: These are attached to the lining of the body wall of segment $3$ to the last,which open on the body surface.
$(iii)$ Septal nephridia: These are present on both sides of the intersegmental septa of segment $15$ to the last,which open into the intestine.