March, 1834. compound animals. 261 



that of the sea-pen, which when touched drew itself into the 

 sand. I will state one other instance of uniform action, though 

 of a very different nature, in a zoophyte* closely allied to 

 Clytia, and therefore very simply organized. Having kept 

 a large tuft of it in a basin of salt water, when it was dark 

 I found that as often as I rubbed any part of a branch, the 

 whole became strongly phosphorescent with a green light : I do 

 not think I ever saw any object more beautifidly so. But the 

 remarkable circumstance was, that the flashes of light always 

 proceeded up the branches, from the base towards the extre- 

 mities. 



The examination of these compound animals was always 

 very interesting to me. What can be more remarkable than 

 to see a plant-like body producing an egg, furnished with 

 setse, and having independent movements, which soon be- 

 comes fixed,branches into numberless arms, and these, though 

 crowded with polypi, yet in some cases possessing indepen- 

 dent organs of movement, and obeying uniform impulses 

 of will? The polyjDi are frequently animals of no simple 

 organization ; and in most respects certainly are to be con- 

 sidered as true individuals. It is therefore more curious 

 to observe, in the young and terminal cells, their gradual 

 formation, from the growth of the simple horny sub- 

 stance of which so many zoophytes are composed. The 

 known organization of a tree should remove all surprise at 

 the union of many individuals together, and their relation to 

 a common body. Indeed we might expect, according to the 

 apparent law, that any structure which prevails in one class 

 wiU be produced in a lesser degree in some others — that since 

 so many plants are compound, so would some animals be thus 

 constructed. It requires, however, a greater effort of reason 

 to view a bud as an individual, than a polypus furnished with 

 a mouth and intestines ; and therefore the union does not 

 appear so strange. 



♦ This coralline emitted a very strong and disagreeable odour, when 

 freshly taken from the sea. 



