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. Dalvell, 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, wliich we kept in 

 sea- water for several days. They increased greatly in size, 

 blowing themselves up, expanding their lobes, and spread- 

 incT 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. 



