These results are quite the same as those of Romanes[I] on Aurelia, Cyanæa, etc., and of Eimer[IV] on Aurelia, Rhizostoma, Cotylorhyza, etc.[b] In these forms Romanes sometimes obtained complete paralysis after the removal of the sensory clubs only, as also after the removal of the whole margin, though this was not marked in Aurelia. In Cyanæa and other forms motor centers seemed to be more abundant than in Aurelia, so that paralysis was oftener followed by recovery. He concludes that while the principal motor centers reside in the lithocysts, other centers doubtless exist that may function vicariously, but that the centers of the margin are more definitely limited to the marginal bodies in the Scyphomedusæ than in the Hydromedusæ, in which the whole margin seems to be replete with centers. He feels positive, furthermore, that no motor centers exist in Aurelia’s margin outside of the marginal bodies (lithocysts). Eimer’s results are essentially the same as Romanes’, so that for a more detailed comparison of the two, Romanes’ works should be consulted. Romanes’ conclusion for the Hydromedusæ is that the motor centers are not so definitely localized in the marginal bodies, but in the margin generally, the excision of the marginal bodies alone producing only partial paralysis, as would also the removal of the margin from between the marginal bodies, but not so marked. For the Hydromedusæ he concludes, then, that all the centers of spontaneity are definitely localized in the margin, but not limited to the marginal bodies. To this he mentions one exception, namely, _Staurophora laciniata_, in which another center is found near the margin and two others in two opposite arms of the proboscis. I made the remark in an abstract (VI) on Conant’s notes that Romanes did not obtain recovery of pulsation after removal of all the lithocysts in Aurelia. As noted above, he did obtain recovery, so that Conant’s results on Charybdea and also Aurelia (see Polyclonia and Aurelia) are quite in agreement with Romanes. The paralysis following the removal of the clubs in Charybdea is evidently, primarily, the result of a loss of a part of its nervous mechanism (motor centers), and, secondarily, of nervous shock, and points to the existence of a definite nervous mechanism in the clubs. The histological evidence is here, as usual, corroborative of the physiological. Another interesting phenomenon observed after the removal of one or all of the clubs was the strange behavior of the proboscis. This would reach from side to side, expanding and contracting its lips as if trying to grasp something. This behavior is very similar to that of the proboscis of _Tiaropsis indicans_ when Romanes stimulated any part of its subumbrella, or of _Limnocodium sorbii_, a little fresh-water medusa, when he stimulated its margin or the region of the radial canals. (Ib., p. 242.)