Androdiaulic

In androdiaulic and triaulic forms the movement of sperm is largely by muscular action, but the function of congealing the sperm into a more or less unitary mass is retained by the prostate.

Two other species of Ringicula have either an incomplete separation of the female and male ducts or a complete separation, becoming an androdiaulic system (see below).

All of the nudibranchs seem to be derived from notaspidean-like stock with androdiaulic reproductive systems.