PENNATULA. 175 



met with in different parts of the ocean. If 

 they possessed in any degree the power of loco- 

 motion, which many natm^alists have ascribed 

 to them, we should be able to ascertain whether 

 all their movements are conducted by a common 

 volition, or whether they are performed inde- 

 pendently of one another. It has often, indeed, 

 been asserted, that pennatulse swim through the 

 water by their own spontaneous movements, 

 consisting either in the waving up and down of 

 the lateral branches, or in the simultaneous im- 

 pulses of the tentacula of all the polypes. Cuvier 

 even represents the polypes of the pennatula as 

 having the power of keeping time, while they 

 are waving the mass through the water, as if 

 they were all actuated by a single undivided 

 volition. But Dr. Grant, who has watched the 

 motions of these animals with great care, is led 

 by his observations to the conclusion that penna- 

 tulae are not in reality possessed of any such 

 locomotive faculty ; but that they are carried 

 to and fro in the ocean, like the gulf weed, 

 without the slightest voluntary power of direct- 

 ing their course. Whatever may be the result 

 of the combined movements of the tentacula, the 

 arms are certainly incapable of those inflexions 

 which have been supposed to supply the means 

 of progressive motion. 



It is only when the contractile flesh of the 

 polypus is released from the restraint which 



