I have said that the principal centers of spontaneity reside in the radial ganglia. Upon further thought this hardly seems warranted. No doubt, among the principal motor centers must be placed the ganglionic masses of the clubs, and the radial ganglia, together with the homologous interradial ganglia, represent centers of equal value. I speak of these two sets of ganglia as homologous, since strictly speaking, they both belong to the margin, and the clubs at whose bases they lie probably represent modified tentacles. Conant’s experiments leave us in the dark as to the function of these ganglia. Next in order, it would seem, are the ganglion cells in the suspensoria, as is suggested by the contractions of an isolated side with a portion of a suspensorium attached. (See previous head.) While we have seen that the frenula and the velarium can contract by themselves, yet, I find no evidence that these can impart their contractions to any adjacent tissue. Conant’s results on cutting the nerve eight times and then continuing the cuts to the base of the stomach are quite the same as Romanes and Eimer obtained upon Aurelia. Romanes, however, concludes that in his Sarsia, Tiaropsis, etc., coördination was broken when only short incisions were made in the margin. Charybdea appears, then, to agree with Aurelia rather than with the Hydromedusæ. Yet, since Romanes at first obtained similar results to those of Charybdea on Sarsia, but on further experimenting concluded that coördination had really been destroyed at the first cutting, we cannot speak with certainty that coördination had not been destroyed in Charybdea before the cuts had been continued to the base of the stomach. I say not with certainty, because the injury to the bell being slight, coördination may have been maintained on the principle of a simultaneously (simultaneous for the octants) alternate exhaustion and recovery of the contractile tissue on the principle of Romanes’ theory. _Stimulation._--Romanes found when he stimulated a deganglionated bell of a Hydromedusa, that it responded by a single contraction, while that of a Scyphomedusa responded with several quite rhythmic contractions. Charybdea in this respect agrees with the Scyphomedusæ. Romanes’ results were also verified on Aurelia. (Experiments 12c, 15, 50, 51.) _Activity of Charybdea._--In speaking of the activity of Charybdea, I cannot do better than refer the reader to the notes. (Experiment 41.) Conant remarks in his dissertation what an active swimmer Charybdea is, and this is further borne out by his later observations. _Temperature._--Ice in the water seemed to have no effect, except when held against an animal, when a slowing of pulsation followed in a few instances. On some pulsating actively in the sun the temperature of the water was found to be 92° F. (Experiments 33-35.)