Cross section through ascidian test to show embedded egg capsules.

1: unitary ascidian test.
2: outer surface of ascidian.
3: short-necked spherical capsule containing up to 3000 ova.
4: extracted capsule; base flattened as from encrusting colonial ascidian with insufficient depth for full development of sphere.
5: translucent dome-shaped lid slightly raised above surface of ascidian.
6: part of lid and flared neck cut away to expose ova.

Llŷn Peninsula, Wales, March 2016.