ME. a. J. EOMANES ON THE LOCOMOTOE SYSTEM OE MEDUSAE. 
741 
to the poison ; thus in a specimen which had been removed from the poison imme- 
diately after the disappearance of reflex irritability had supervened, recovery began in 
ten minutes after re-immersion, and was complete in half an hour. 
In Ticirojtsis the symptoms of nicotin-poisoning are also well marked. When 
gradually administered, the first effect of the narcotic is a complete loss of coordination 
in the swimming-motions. A slight increase of the dose brings about a tonic spasm, 
which differs from the natural spasm of these animals — (a) in being stronger, so 
that the nectocalyx becomes ball-shaped rather than square, ( b ) in being much more 
persistent, and ( c ) in undergoing variations in its intensity from time to time, instead 
of being a contraction of uniform strength ; thus the spasm temporarily affects 
some parts of the nectocalyx more powerfully than other parts, so that the organ may 
assume all sorts of shapes. Such distortions proceed even further under the influence 
of nicotin than under that of strychnine, &c. Sometimes, for instance, one quadrant 
will project in the form of a pointed promontory; at other times two adjacent or 
opposite quadrants will thus project, and occasionally all four will do so, the animal 
thus becoming star-shaped. Sometimes, again, one quadrant will be less contracted 
than the other three, while at other times more or less slight relaxations affect 
numerous parts of the bell, its margin being thus rendered sinuous, though more or 
less violently contracted in all its parts. This state of violent spasm lasts for several 
minutes, when it gradually passes off, the nectocalyx relaxing into the form of a deep 
howl and remaining quite passive, except that every now and then one part or another 
of the margin is suddenly contracted in a semilunar form. By-and-by, however, even 
these occasional twitches cease, and the animal is now insensible to all kinds of stimu- 
lation. Recovery in normal water is gradual, and marked in its first stage by the 
occasional retractions of the margin last mentioned. At about this stage also, or 
sometimes slightly later, the animal first becomes responsive to stimulation ; and it is 
interesting to note that the response is performed, not by giving a general spasm as 
would the unpoisoned animal, but by folding in the part irritated — an action which very 
much resembles, on the one hand, the spontaneous convulsive movements just described,, 
and, on the other, the response which is given to stimulation by the unpoisoned bell 
when gently irritated after removal of its margin. After these stages there supervenes 
a prolonged period of quiescence, during which the animal remains normally responsive 
to stimulation. Spontaneity may not return for several hours, and, after it does return, 
the animal is in most cases permanently enfeebled. Indeed, on all the species of 
Medusae, nicotin, both during its action and in its subsequent effects, is the most deadly 
of all the poisons I have tried. 
§ 9. Alcohol . — The solution must be strong to cause complete intoxication. The 
first effect on Sarsia is to cause a great increase in the rapidity of the swimming-motions 
— so much so, indeed, that the bell has no time to expand properly between the occur- 
rence of the successive systoles, which, in consequence, are rendered feeble. These 
motions gradually die out, leaving the animal quite motionless. The nectocalyx is now 
5 L 2 
