Balanoglossus, affinities of Nemertinea with, [120]
Balatro, [204], [212], [224], [227]
Balfour, on Trochosphere, [229]
Barentsia, [488] n.
Barrois, on Polyzoa, [509]
Basement-membrane, of Leptoplana, [11], [12];
of Nemertines, [102], [103], [110] f.
Bathymetrical distribution, of Polychaeta, [300]
Bdellodrilus, [376]
Bdelloida, [201], [203] f., [211], [213], [215], [216], [222], [227]