To answer the second of the above questions, I placed an Aurelia with its concave surface uppermost, and removed seven of its lithocysts; I then observed the spontaneous discharge of the remaining one, and found it to be conspicuous enough that, after the occurrence of one of the natural pauses (if this were of sufficient duration), the first contraction was feeble, the next stronger, the next still stronger, and so on, till the maximum was attained. This natural staircase action admits of being very prettily shown in another way. If a tolerably large Aurelia is cut into a spiral strip of small width and great length, and if all the lithocysts are removed except one at one end of the strip, it may be observed that, after the occurrence of a natural pause, the first discharge only penetrates perhaps about a quarter of the length of the strip, the next discharge penetrates a little further, the next further, and so on, till finally the contraction waves pass from end to end. On now removing the ganglion, waiting a few minutes, and then stimulating with successive induction shocks, the same progressive penetration is observable as that which previously took place with the ganglionic stimulation. Lastly, the identity of natural and artificial staircase action may be placed beyond all doubt by an experiment in which the effects of induction shocks and of ganglionic discharges are combined. To accomplish this, all the lithocysts save one are removed, and a staircase is then built up in the ordinary way by successive induction shocks. It will now occasionally happen that the ganglion originates a discharge during the process of constructing the staircase, which is being built up by the artificial stimuli; when this happens the resulting contraction takes its proper rank in the series, and this at whatever point the natural contraction happens to come in.