These organisms live in cockles, oysters and other lamellibranchs and they so affect the gonads of these molluscs as to castrate and sterilize their host.
On the floor of the stomach are borne the conspicuous gonads (ov), and also tentacle-like processes termed gastric filaments or phacellae, projecting into the cavity of the stomach.
We therefore regard the body of a Cestode as a single organism within which the gonads have become segmented, and the segmentation of the body as a secondary phenomenon associated with diffuse osmotic feeding in the narrow intestinal canal.
The segments occupied by the gonads are fixed, and are for earthworms invariably X, XI.
The gonads or generative organs may be produced either in the ectoderm or the endoderm.
Cunoctantha fowleri Browne, buds are formed from the sub-umbrella on the under side of the stomach pouches, where later the gonads are developed.
The gonads originate by proliferation of the anterior wall of the pericardium.
It seems that the posterior nephridia are mainly gonad ducts, and the gonads are developed in close association with the funnels.
The blood of most species behaves differentially towards precipitants, and it is therefore conceivable that when blood is used as food and is elaborated into special compounds for the nutrition of the reproductive organs of a parasite, these specific or larger differences in the blood of animal hosts may prevent the ripening of the gonads of a widely diffused parasite and only one particular kind of blood prove suitable.
Shoe-shaped gonads (ov) mark, Oral arms. ing four stomach-pouches, b t tentacles.