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VII. Concluding Observations on the Locomotor System of Medusa ?. 
By George J. Romanes, M.A., F.L.S. 
Communicated by Professor T. H. Huxley, LL.D., Sec . R. S. 
Received December 30, 1878,—Read January 16, 1879. 
In my previous papers on this subject the considerations are sufficiently explained 
which originally induced me to defer any systematic investigation concerning the his¬ 
tology of the Medusae, until the more important of the physiological observations 
should have been completed. While preparing the material for these papers, I was 
not blind to the fact that it served still further to ripen the promise that a careful 
development of the histology of the Medusae would prove highly remunerative in mor¬ 
phological results. But I felt that, even if no other workers should enter the field 
from the side of morphology, it was more desirable that the physiology of these 
primitive nervous tissues should be speedily worked out than that their structural 
peculiarities should be so. Whether or not this view was a wise one, in the result it 
has proved beneficial; for not only was I fortunate enough to procure the co-operation 
of so competent an histologist as my friend Mr. Schafer in working out the histology 
of the covered-eyed Medusae, but contemporaneously with his researches there was also 
being carried on by Messrs. 0. and R. Hertwig a most painstaking and thorough 
investigation of the histology of the naked-eyed Medusae. At the same time, also, 
Professor Eimer had been continuing his microscopical researches. In this way, there¬ 
fore, both the physiology and the morphology of the Medusae were simultaneously 
worked out in parallel lines, with the result of furnishing a much larger and more 
complete body of information than could possibly have been obtained by a single 
observer in double the time. 
Of Professor Eimer’s microscopical work it would be now premature to speak, for as 
yet he has only published a somewhat meagre abstract, with the promise, however, of 
shortly supplementing it with a more complete and detailed exposition. Of Mr. 
Schafer’s work I have previously spoken in the highest terms, and before the present 
remarks will be in print the Eellows of the Royal Society will themselves be in a 
position to appreciate its merits. Of Messrs. Hertwig’s work it is difficult to speak 
without enthusiasm; but as I shall conclude this paper with a brief resume of the 
present literature on the morphology of the Medusae, it is needless that I should here 
dwell on this, the most meritorious of its existing memoirs. 
Understanding that Mr. Schafer is still prosecuting his investigations, and observ- 
MDCCCLXXX. Y 
