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been removed. He describes them as “several irregular , inefficient, and feeble contractions 
of a local nature which rarely last any considerable time.” This is no doubt partly true 
of some cases, but it is not true of all. I have frequently seen these after contractions as 
rhythmical (though this is rare), as effectual, and as powerful as those which had been 
previously supplied by the single remaining lithocyst. Moreover these contractions may 
usually be seen to emanate from some very localized portion of tissue, and from thence 
to radiate over the whole substance of the umbrella, just as the contractile waves which 
emanated from a single remaining lithocyst had previously done. On now cutting out 
this localized portion of tissue, the umbrella usually becomes again paralyzed, while 
the portion of tissue which previously animated it may be seen to continue its con- 
tractions after the manner of excised lithocysts. I did not pay sufficient attention to 
the number of hours after excision of the lithocysts during which these secondary 
movements continued, to admit of my speaking with confidence on this point ; but so 
far as I can recollect my numerous experiments with this species, it is certainly not 
correct to say that these contractions “ generally ceased after a few moments.” My 
impression is that they usually last for several days. I agree with Dr. Eimer, how- 
ever, that, as a general rule, the secondary movements in Aurelia aurita are not so 
persistent as the primary ones, and also that in this species, under some circumstances, 
insensibility to stimulation rapidly supervenes upon loss of spontaneity. This, however, 
is far from being always the case with Aurelia aurita, and is not even generally the 
case with some other species — Cyanoea caffillata, for instance, continuing to respond 
even to slight stimulation two or three days after it has been completely paralyzed by 
the removal of its lithocysts, and this even though it be kept in a small jar without 
change of water. Again, if the lithocysts be left in situ and the animal be kept in a 
confined body of water, irritability will continue for days after all the usual indications 
of spontaneity have disappeared. Nevertheless, with but slight modifications, I have 
confirmed Dr. Eimer’s experiment of placing different specimens of Aurelia aurita 
under similar conditions, removing the lithocysts of some and not of others, and 
observing that those individuals which had been operated upon died sooner than those 
which had not. 
These experiments, however, and many others entailing similar precautions, I do not 
intend to publish until next year, when I hope to have the opportunity of conducting 
them in a more satisfactory manner. 
I am also able to confirm Dr. Eimer’s statements regarding the behaviour of bisected 
Aurelias ; and I think with him that it is not improbable that halves, quarters, or eighths 
of such Medusae would, under suitable conditions, redevelop into entire animals. 
Dr. Eimer’s very interesting statement, to the effect that an Aurelia before its mutila- 
tion contracts twice, four, or eight times as rapidly as do its half, quarter, or eighth 
part after mutilation, is a statement which I am unable either to confirm or to dispute. 
I did indeed observe, in a general way, that the smaller segments of an Aurelia mani- 
fested a slower rhythm than the larger segments ; but it never occurred to me to test 
