Mr. C. Collingwood on Oceanic Forms of Hydrozoa, 311 
the deck, ran about like a frantic maniac, so that it took several 
men to catch him, and, when secured and the proper remedies 
applied, he rolled about for a considerable time, groaning with 
pain. His arm was red, inflamed, and swollen, and remained so 
for some hours after the occurrence. 
One circumstance in relation to these large Physalie struck 
me as being very remarkable. Each one as it floated by had 
beneath it what at first I took to be its mass of tentacles and 
polypites; but on more close observation I found that the 
appearance was due to a shoal of small fishes accompanying the 
hydrozoon under protection of its appendages. The fishes were 
of various sizes, from 2 to 6 inches long, transversely banded, 
and looking in the water precisely like the pilot-fish (Naucrates 
ductor). There were perhaps a dozen of these accompanying 
fish clustered together beneath the bladder of each Physalia. 
Every Physalia had its cluster; but this peculiarity was ob- 
servable—viz. that under small Physalia the fishes were small, 
while under large specimens they were correspondingly large, 
being, in fact, always proportioned to the size of the man-of-war 
which they accompanied. Unfortunately I did not discover this 
curious fact till late in the day; and when the boat was down 
in the morning I was unaware of it, or I should have made a 
point of attempting to secure a specimen of so interesting a 
fish. 
_What the relation is which exists between the fish and the 
Hydrozoon I cannot say; but this correspondence between the 
sizes of the two animals seems to indicate that the fishes do not 
capriciously select their protecting Hydrozoon. It is known 
that certain fishes harbour in the threads of some of the large 
Lucernaride ; but I believe they have not before been noticed 
accompanying Physalie. 
The presence of these fishes also accounted for a remarkable 
thing I had observed earlier in the day. One of the large 
albicores made a sudden dash at a Physalia (apparently), but did 
not take it; returning, however, presently to the charge, he 
made a clean sweep, no trace of the Physalia being left. Doubt- 
less it was the small fishes which accompanied it, rather than 
the Physalia itself, which stimulated the albicore’s attack. 
Before I quit the subject -of the Physophoride, I must not 
omit to mention a circumstance which occurred only once 
during the whole time I was at sea—viz. the remarkable influx 
of Stephanomiadz, accompanied by other kinds of animals, into 
Kelung Harbour, Formosa, on the 18th of June. The beautiful 
organisms I there observed were of the genus Stephanomia, and 
closely resembled the S. triangularis of Quoy and Gaimard. They 
were wonderfully sculptured and carved masses of solid jelly, 
