Reprodutive System.

The reproductive system is marked by the great development of the accessory glands, and by a distinction between the male and female portions of the atrium. This latter is in the shape of an H, the anterior portion being the atrium masculinum and the posterior the atrium femininum.

Seminal products are collected by four vasa efferentia, and are passed into the atrium masculinum by the median seminal duct, which may be closed by the extension of the anterior adenodactylus. At the dorsal edge of the median seminal duct opening there opens the duct of the prostate gland, which secretes bright red globules to mix with the seminal products.

The oviduct opens, in the corresponding position to the median seminal duct, into the atrium femininum. The sequence of events is hard to follow, but the egg and yolk products seem to pass into the dorsal portion of the atrium femininum, where fertilisation takes place. The shell is then secreted round the mass and the whole egg is forced out of the genital pore by the action of the muscular processes. It is certain that the male and female gonads are functional at the same time, and self-fertilisation must take place in a percentage of the cases. However, copulation takes place, the head of one worm being applied to the tail of another, so that there can be mutual interchange.

There are three adenodactyli, one between the prostate gland and the ductus seminalis, a large median one separating the atrium masculinum and the atrium femininum, the third above the opening of the oviduct.