196 HISTORY OF BRITISH ZOOPHYTES. 
turalists of note deny that it has this power. Lamarck 
and Schweigger, reasoning from analogy, deny it, and Dr. 
Johnston, speaking from observation, states that, when 
placed in a basin of sea-water, they are never observed to 
change their position, but they remain on the same spot, 
and lie with the same side up, just as they have been put 
in. Sir J. G. Dalyell, who at various times has had so 
many living specimens, states, “ Further than complete dis- 
tension of the whole specimen, whereby its dimensions may 
be quadrupled, no approximation to motion is betrayed. 
Neither does such distension, though to the utmost, reduce 
its specific gravity sufficiently to produce an equilibrium 
with the water. Thus the animal cannot swim.” We have 
had two or three fine live specimens, which we kept in 
sea-water for several days. They increased greatly in size, 
blowing themselves up, expanding their lobes, and spread- 
ing out their tentacula from a kind of sheath that covers 
them when contracted. We were on the watch for some 
locomotion when the several parts were so swollen, but 
when laid on the bottom of the jar they could not elevate 
themselves, nor turn the polype-bearing side of the lobes up 
if placed with their face downwards. 
We did observe, however, that they were phosphorescent, 
