356 HISTORY OF BRITISH ZOOPHYTES. 
confess that when seen by the naked eye, it has not much 
to recommend it. As it is pretty much the colour of the 
Fucus that it invests, it takes a tramed eye to observe it at 
all; and when it is seen, what is it, some would say, but a 
brownish fleshy scarf, with some scattered spinules, giving 
roughness to what would otherwise be a smooth glisten- 
ing surface? If you would look at Sir John G. Dalyell’s 
pretty figure of it, plate ix., or if I had room to tell you 
all that he and the Rev. T. Hincks, of Exeter, have written 
respecting it, you would own that there is more in this 
“rough sea-mat” than at first meets the eye. “When 
plunged in recent sea-water,” says the Baronet, “a thin 
pale blue cloud will be speedily interposed between its dark 
irregular surface and the spectator’s eye. Let the vessel 
sustain a shock; the cloud is instantaneously dispelled, 
while the brownish fleshy substance remains prominent as 
before. This illusion may be frequently repeated. The 
semblance of a cloud arose from a multitude of hydre 
elicited from the cells whither they had retreated, to enjoy 
the freshness of the renovated element. ‘Their numerous 
pale tentacula in motion over the darker ground, caused a 
misty shade.” 
“When immersed in sea-water, first a very short white 
