The ovaries arise like the testes as rounded bodies in the ligament.
These sacs contain the developing sperm cells or eggs, and are with very few exceptions universal in the group. The testes are more commonly thus involved than are the ovaries.
Gonads limited in number of pairs, testes and ovaries always present in the same individual.
The .- trunk contains a spacious body-cavity filled during the breeding season by the swollen ovaries, and the same is true of the tail if we substitute testes for ovaries.
In Acanthobdella the testes are, however, not contained in the general coelom, and the nephridia lie in the septa.
The body bears tentacles, but shows no division into hydrorhiza, hydrocaulus or hydranth; it is temporarily fixed and has no perisarc. The polyp is usually hermaphrodite, developing both ovaries and testes in the same individual.
Entocolax, mouth at free extremity, animal fixed by aboral orifice of pseudopallium, Pacific. Entoconcha, body elongated and tubular, animal fixed by the oral extremity, protandric hermaphrodite, parasitic in testes of Holothurians causing their abortion.
Hermaphrodite, the ovaries and testes distinct, with separate apertures.
The former consist of one pair or more of vesicular testes communicating by fine ducts with a vesicula seminalis.
The testes in the pairing-season form projections in the groins, but (except in the Duplicidentata) do not completely leave the cavity of the abdomen.