Trophonia, [299], [334];

genital organs, [273];

head, [262];

intestine, [271]

Trunk, of Nereis, [246];

of Polychaeta, [259];

of Gephyrea, [412] f.

Tube, of Rotifers, [205];

of Polychaeta, [287] f.; composition of, [290];

fossil, [301], [302];