BUGGED SOUP ARIA. 225 



straggle across the branches in various directions. 

 They are of great length, and are formed of the com- 

 mon horny substance of the cells, from which they 

 originate. If we trace them carefully, we shall find 

 that they always spring from a sort of socket placed 

 near the summit of the cell, on its outer side. Some- 

 times they seem to be branched, but most usually 

 they are obviously simple throughout ; and as they 

 are connected by their extremities with other distant 

 branches, their nature is doubtless the same as that 

 of the root-threads, and their use that of affording 

 mutual support to the branches, which otherwise 

 might be liable to be broken off by the waves, or by 

 the trampling of crabs, and other animals. 



By a little careful searching we may easily find, in 

 exactly similar situations, another species very closely 

 like this, but displaying some interesting points of 

 diversity. It is known as the Kugged Scuparia. 

 You would scarcely discern any difference between 

 this specimen and what we have just been examining, 

 except that this is rather more erect, less creeping in 

 its manner of growth. ISTor, even when brought 

 under the microscope, would you instantly be struck 

 with the distinction. Yet distinction there is. 



In this Scuparia the membranous aperture is not 

 protected by the arching fan-like operculum, nor by 

 any organ answering to it. But, as if to compensate 

 for this defect, there are some special organs of defence 

 which were wanting in the Canda. One of these is 

 called the vibraculum, or the whiplash. At the back 



p 



