What is the Difference Between Protonephridia and Metanephridia
The main difference between protonephridia and metanephridia is that protonephridia are a network of dead-end tubules without internal openings, whereas metanephridia are a type of excretory glands with a ciliated funnel opening into the body cavity. Furthermore, protonephridia occur in the phyla Platyhelminthes, Nemertea, Rotifera, and Chordata (Lancelets), while metanephridia occur in the phyla Annelida, Arthropoda, and Mollusca.
Protonephridia and metanephridia are two types of nephridia that mainly occur in invertebrates. Generally, they are functionally analogous to the vertebrate kidney and are responsible for the removal of metabolic waste from the body.