ME. Gr. J. EOMANES ON THE LOCOMOTOE SYSTEM OF MEDUSAE. 
299 
so characteristic of Cyancea capillota. Instead of the heart-like regularity with which 
systole and diastole follow one another in the unpoisoned animal, we now have periods 
of violent and prolonged systole resembling tonic spasm ; and when the severity of this 
spasm is for a moment abated, it is generally renewed before the gonocalyx has had 
time again to become fully expanded. Moreover the spasm itself is not of uniform 
intensity throughout the time it lasts ; but while the gonocalyx is in a continuously 
contracted state, there are observable a perpetual succession of extremely irregular 
oscillations in the strength of the contractile influence. It is further a highly interest- 
ing fact that the convulsions are very plainly of a paroxysmal nature. After the gono- 
calyx has suffered a prolonged period of convulsive movements, it expands to its full 
dimensions, and in this form remains for some time in a state of absolute quiescence. 
Presently, however, another paroxysm supervenes, to be followed by another period of 
quiescence, and so on for hours. The periods of quiescence are usually shorter than are 
those of convulsion ; for while the former seldom last more than forty seconds or so, the 
latter may continue uninterruptedly for five or six minutes. In short, Medusae, when 
submitted to the influence of strychnia, exhibit all the symptoms of strychnia poisoning 
in the higher animals. Death, however, is always in the fully expanded form. 
( d ) Curare has already been tried upon Medusae, and is stated to have produced no 
effects ; it is therefore especially desirable that I should first of all describe the method 
of exhibiting it which I employed. 
Having placed the medusid to be examined in a flat-shaped beaker, I filled the latter 
to overflowing with sea-water. I next placed the beaker in a large basin, into which I 
then poured sea-water until the level was the same inside and outside the beaker, i. e. 
until the two -bodies of water all but met over the brim. Having divided the medusid 
across its whole diameter, with the exception of a small piece of marginal tissue at one 
side to act as a connecting-link between the two resulting halves, I transferred one of 
these halves to the water in the basin, leaving the other half still in the beaker, the 
marginal tissue which served to unite the two halves being thus supported by the rim 
of the beaker. Over the minute portion of the marginal tissue which was thus of 
necessity exposed to the air, I placed a piece of blotting-paper which dipped freely 
into the sea-water. Lastly, I poisoned the water in the beaker with successive doses of 
curare solution. 
The results obtained by this method were most marked and beautiful. Previous to 
the administration of the poison both halves of the medusid were of course contracting 
vigorously, waves of contractile influence now running from the half in the beaker to 
the half in the basin, and now vice versa. But after the half in the beaker had become 
effectually poisoned by the curare, all motion in it completely ceased, the other, or 
unpoisoned half continuing to contract independently. I now stimulated the poisoned 
half by nipping a portion of its margin with the forceps. Nothing could be more 
decided than the result. It will be remembered that when any part of Staurophora 
laciniata is pinched with the forceps or otherwise irritated, the motion of the whole 
