296 
MR. Gr. J. ROMANES ON THE LOCOMOTOR SYSTEM OE MEDUSA]. 
Having put two or three hundred Sarsice into a large bell-jar, I completely shut out 
the daylight from the room in which the jar was placed. By means of a dark lantern 
and a concentrating lens, I then cast a beam of light through the water in which the 
Sarsice were swimming. The effect upon the latter was most decided. From all parts 
of the bell-jar they crowded into the path of the beam, and were most numerous at that 
side of the jar which was nearest to the light. Indeed close against the glass they 
formed an almost solid mass, which followed the light wherever it was moved. The 
individuals composing this mass dashed themselves against the glass nearest the light 
with a vigour and determination closely resembling the behaviour of moths under 
similar circumstances. There can thus be no doubt about Sarsia possessing a visual 
sense. 
The method of ascertaining whether this sense is lodged in the eye-specks was, of 
course, extremely simple. Choosing a dozen of the most vigorous specimens, I removed 
all the eye-specks from nine, and placed these together with the three unmutilated ones 
in another bell-jar. After a few minutes the mutilated animals recovered from their 
nervous shock, and began to swim about with tolerable vigour. I now darkened the 
room, and threw the concentrated beam of light into the water as before. The differ- 
ence in the behaviour of the mutilated and of the unmutilated specimens was very 
to have occupied with regard to this matter from that which ventured upon bold assertions as to the specific 
function of these organs. Now, forasmuch as the above paragraph in the text was written without reference 
to Prof. Haeckel’s work, I should here like to add the remark that, in my opinion, his deductions concerning 
this matter differ from those of previous writers in the important particular that they were warranted by the 
facts of structure which he observed. Granting that he had satisfied himself as to the nervous character of 
the tissue he describes, and the peculiarly significant distribution of this tissue in the marginal vesicles which 
he figures appears to me certainly to justify his conclusion that “ was die Deutung der Randkorperchen nach 
Feststellung dieses complicirteren Baues anlangt, so wird zunachst ihre allgemein giiltige Stellung als Sinnes- 
organe dadurch nur befestigt.” And it is of course needless to say that with the next succeeding sentences I 
fully concur. “Was aber die speciellere Eeststellung der Sinnesqualitat betrifft, so scheint mir diese dadurch 
nach keiner Richtung hin hestimmter bezeichnet zu werden. Im Gegentheil glaube ich, dass damit nur die 
wesentliche Differenz dieser Randblaschen von anderen ahnlichen Sinnesorganen niederer Thiere, z. B. von den 
meist zunachst damit verglichenen Gehorblaschen der Wiirmer und MoRusken, noch mehr bestatigt und aus- 
driicklich hervorgehohen wird Noch weniger freilich als die von den meisten Autoren angenommene 
Deutung der Randblaschen unserer Medusen als Gehororgane kann die von Agassiz und Fritz Muller vertre- 
tene Ansicht befriedigen, dass dieselben Augen seien Alle diese Yerhaltnisse sind mit der Deutung der 
Concretion als ‘ Linse ’ und des sie umschliessenden Sinnesganglion als ‘ Sehnerv ’ durchaus unvereinbar.” 
It may not be unnecessary to say that, although the simple experiment above described effectually proves 
that the marginal bodies have a visual function to subserve, we are not for this reason justified in concluding 
that these bodies are so far specialized as organs of sight as to be precluded from ministering to any other sense. 
Therefore the results of the above-mentioned experiments cannot be held in any way to affect the judgment of 
Prof. Haeckel : — “ Und doch ist es viel wahrscheinlicher, dass hier wesentlich andere Sinnesempfindungen zu 
Stande kommen, von deren eigentlicher Qualitat wir uns keine bestimmte Yorstellung machen konnen; wie es 
z. B. sehr wahrscheinlich ist, dass die Empfindung der Licht- und Schallwellen, fiir welche bei den hoheren 
Thieren verschiedene Organe differenzirt sind, bei den niederen an ein und dasselhe Sinnesorgan, natiirlich in 
unvollkommener Ausbildung, gebunden vorkommen.” (For the quotations vide loc. cit. pp. 57, 58.) — Feb. 1876.] 
