Unicellular organisms, immortality of, [25], [27].
Unio, length of life of, [56], [57].
Valaoritis, on origin of germ-cells, [195];
on physiological value of, [246].
Vanessa cardui, length of life of, [43];
V. prorsa, [44];
V. urticae, [44];
V. levana, deposition of eggs of, [94].
Variations, always present, [101].
Ventral canal cell, [223].