Give the name of the excretory organ present in the following animals.
(i) Rotifers (ii) Cockroaches
(iii) Lancelets (iv) Amphioxus
(i) Rotifers — Flame cells
(ii) Cockroaches — Malpighian tubules
(iii) Lancelets — Protonephridia
(iv) Amphioxus — Nephridium