10 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 



Cotylorhyza, etc.* 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 Cyanaea 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 Scyphomedusae 

 than in the Hydromedusse, 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 1 works 

 should be consulted. 



Romanes' conclusion for the Hydromedusaa 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 Hydromedusae 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 



* Eimer's results I get from Romanes and Hesse" 1 . 



