The only outward characteristic by which the males can be distinguished from the females is the presence in the former of a small white papilla on the ventral side of the 17th pair of legs (Pl. 47, fig. 4). At the extremity of this papilla the modified crural gland of the last leg opens by a slit-like aperture.
The generative orifice in both sexes is placed on the ventral surface of the body, close to the anus, and between the two anal papillæ, which are much more marked in small specimens than in large ones, and in two cases (of females) were observed to bear rudimentary claws.
1. The Male Organs. Pl. 53, fig. 43.
The male organs consist of a pair of testes (te), a pair of prostrates (pr) and vasa deferentia (vd) and accessory glandular tubules (f).
All the above parts lie in the central compartment of the body-cavity. In addition, the accessory glandular bodies or crural glands of the last (17th) pair of legs [TN22] are enlarged and prolonged into an elongated tube placed in the lateral compartment of the body-cavity (ag).
The arrangement of these parts represented in the figure appears essentially that which Moseley has already described for this species. The dilatations on the vasa deferentia, which he calls vesiculæ seminales, is not so marked; nor can the peculiar spiral twisting of this part of the vas deferens which he figures (No. 13) be made out in this specimen. The testes are placed at different levels in the median compartment of the body-cavity, and both lie on the same side of the intestine (right side).
The arrangement of the terminal portions of the vas deferens is precisely that described by Moseley. The right vas deferens passes under both nerve-cords to join the left, and from the enlarged tube (p), which, passing beneath the nerve-cord of its side, runs to the external orifice. The enlarged terminal portion possesses thick muscular walls, and possibly constitutes a spermatophore maker, as has been shewn to be the case in P. N. Zealandiæ, by Moseley.
In some specimens a different arrangement obtains, in that the left vas deferens passes under both nerve-cords to join the right.
In addition to the above structures, which are all described by Moseley, there are a pair of small glandular tubes (f), which open with the unpaired terminal portion of the vas deferens at the generative orifice.
2. Female Organs. Pl. 52, fig. 33.