Obtaining gametes and embryos of ascidians.

Ascidians are basal chordates that have become increasingly important for understanding chordate evolution. They comprise three orders. In the orders Phlebobranchia and Stolidobranchia, most species freely spawn eggs and sperm, whereas members of the order Aplousobranchia form colonies that brood their eggs and broadcast sperm. In the two free spawning orders, eggs and sperm are easily obtained for in vitro fertilizations. In the third order, slices of colonies yield gametes and embryos of all stages. Methods are described for obtaining gametes, performing fertilizations, and culturing embryos. Also included are methods for removing follicle cells and vitelline coats from oocytes.