Excretory Organs of Branchiostoma (With Diagram) | Chordata | Zoology
The excretory organs of Branchiostoma are ectodermal in origin and comparable with the nephridia of annelids and platyhelminthes. The excretory organs of Branchiostoma are different from the kidney of vertebrates. Protonephridia: The protonephridia of Branchiostoma are simple, closed ciliated saclike and thin-walled ectodermal tubules. These are about 90 to 100 pairs arranged segmentally on dorso-lateral pharyngeal wall, one above each [...]