In C. nigrescens and in some other species a zooid may contain a pair of ovaries, a pair of testes, or an ovary and a testis, although the males, females and hermaj phrodites do not differ from one another in external characters.
The efferent ducts are ciliated, and there is a patch of cilia at the point where they communicate with the cavity of each testis.
The testis is a single compact organ.
Recent research, however, points to these cords of the rete testis et ovarii as being derived from the coelomic epithelium instead of from the mesonephros.
For some years he lived in seclusion in Cornwall and occupied himself with theological studies, producing among other books The Arte of Happines (1619) and Testis Veritatis, a reply to Richard Montagu's Appello Caesarem.