LUMINOUS POLYPI. 
177 
The currents were against us the greater part of the 
distance, and we did not get into the Guinea stream 
till we were very near the termination of our voyage. 
We twice passed through large fields or patches of 
water, having a light brown or fawn-coloured tinge 
from the presence of fine particles, by our seamen popu- 
larly called “ Whalesfood,” but which in reality were 
nothing more than diminutive filamentous conferva;, 
very similar to those observed by Mr. 0. Darwin 
on the eastern coast of South America. As the 
luminosity of the sea appeared to be much in- 
creased when these were present, we were induced to 
examine the water frequently and carefully, with a very 
powerful compound microscope. Three phosphores- 
cent mollusca were discovered, but so minute that we 
were unable to decide the species. The most nume- 
rous and apparently the most important, was a tiny, 
circular, transjiarent, gelatinous mollusk, congregated 
in little masses or bundles, without any evident rays 
or feelers, but which after being shaken gently a few 
times, separated; each particle continuing to emit its 
scintillation of light on being moved. The second 
in frequency was a brownish disc with a circle of 
minute rays or feelers ; the scat of luminosity appa- 
rently in the centre. The third was a series of two 
or more curved gelatinous tubes, partially fitting into 
each other, and which also separated on motion, each 
retaining its luminous property. 
In all cases where we examined the water, it 
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VOL. II. 
