ME. Gr. J. EOMANES ON THE LOCOMOTOE SYSTEM OE MEDTTSiE. 
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will be observed that, so far as the movements in question are themselves concerned, 
they are undistinguishable from an ordinary reflex act — such, for instance, as we have 
observed to occur in Sarsici. But we are accustomed to hear that for the occurrence of 
a truly reflex act, the presence of ganglionic or central nerve-matter is requisite. Yet 
in the case before us we have exceedingly precise action of an apparently reflex kind, 
which is nevertheless quite independent of the only ganglia that can be shown to occur 
in the organism. In view of this fact, therefore, I was led to think it probable that 
the reflex centres I was in search of might be seated in the polypite. Accordingly I 
cut off the polypite, and tried stimulating its own substance directly. I found, however, 
that no matter how small a portion of this organ I used, and no matter from what part 
of the organ I cut it, this portion would do its best to bend over to the side which I 
irritated. Similarly, no matter how short a stump of the polypite I left in connexion 
with the nectocalyx, on irritating any part of the latter, the stump of the polypite 
would deflect itself towards that part of the bell, although of course, from its short 
length, it was unable to reach it. Hence there can be no doubt that every portion of 
the polypite — down, at least, to the size which is compatible with conducting these 
experiments — is independently endowed with the capacity of very precisely localizing a 
point of irritation which is seated either in its own substance or in that of the bell*. 
We have here, then, a curious fact, and one which it will be well to bear in mind 
during our subsequent endeavours to frame some sort of a conception regarding the 
nature of these primitive nervous tissues. The localizing function which is so very 
efficiently performed by the polypite of this Medusa, and which, if any thing resembling 
it occurred in the higher animals, would certainly have definite ganglionic centres for 
its structural correlative, is here shared equally by every part of the exceedingly tenuous 
contractile tissue that forms the outer surface of the organ. I am not aware that such 
a diffusion of ganglionic function has as yet been actually proved to occur in the animal 
kingdom ; but I can scarcely doubt that future investigation will show such a state of 
things to be of common occurrence among the lower members of that kingdom f. 
* It must here be added that the same remark may he made with reference to the nectocalyx ; for however 
small a part of this organ is excised, it will bend inwards on being irritated. This case, however, is not 
nearly so remarkable as is that of the polypite, because, in the first place, there is no choice of direction to be 
icxercised, and, in the next place, this bending inward of the nectocalyx upon irritation occurs more or less in 
the case of all the species of this genus, and is no doubt identical with the spasmodic movement exhibited 
under similar circumstances by Staurophora laciniata, to which attention was directed in my last paper, and 
which will form the subject of the next section of the present one. The only respect in which, so far as I can 
see, the inflexion of the seat of irritation in Tiaropsis indiccins is distinguishable from the spasm of some other 
species of Tiaropsis and of Staurophora consists in its being of a local instead of a general character. 
t The only case I know which rests on direct observation, and which is at all parallel to the one above described, 
is the case of the tentacles of Drosera. Mr. Darwix found, when he cut off the apical gland of one of these 
tentacles together with a small portion of the apex, that the tentacle thus mutilated would no longer respond 
to stimuli applied directly to itself. Thus far the case differs from that of the polypite of Tiaropsis indicans, 
and in respect of localization of coordinating function resembles that of ganglionic action. But Mr. Darwin 
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