21 
1:883.] Compound Organisms and their Lessons. 
existence. Each feeds, digests, and assimilates without — as 
in the zoophytes — throwing the product of its digestion into 
one common stock. Each reproduces itself both by eggs 
and buds. The eggs give rise to new, unconnected indivi- 
duals, whilst the buds increase the specimen before us. 
There is no general nervous system, no circulatory apparatus 
connecting the whole colony together. The removal of a 
portion, and the death of its zooids, inflicts no perceptible 
injury on the remaining part. If it be asked how the whole 
adheres together ? the answer is easy : the cell-wall of each 
zooid adheres to the cell-wall of its neighbour, forming thus 
a continuous structure. It is evident that while such a 
Flustra lives on and increases, its component zooids die in 
succession and are replaced by their offspring, particular life 
and death succeeding each other within a more general life. 
As a matter of course an entire Flustra, like an entire 
zoophyte, is not limited in the number, the shape, and the 
size of its ramifications. Here, therefore, one of the dis- 
tinctions between animals and plants proposed by our old 
master Oken falls to the ground. He maintained that the 
animal was geometrically and arithmetically limited and 
definite, whilst the plant was neither. Thus we know the 
number of the limbs and other parts of a normal unmuti- 
lated animal of the higher classes ; we know their shapes, 
and their respective positions. But we do not know the 
number of branches and twigs which a tree of any kind 
ought to have, nor yet their shape or their relative positions. 
But if Oken had taken the zoophytes into consideration he 
would have found in the entire animal— i.e., in the product 
of a single egg — as little regularity of form and number as 
in the tree, the product of a single seed. Definite regular 
structure is found in the one case in the zooid, and in the 
other in the flower-bud. 
But an indication or forthshadowing of compound life may 
be traced in higher forms than those which we have just 
been considering. Among the Annuloida we find a well- 
known and disreputable being, the tape-worm. This creature 
has indeed a head, but otherwise it consists of a multitude 
of segments familiarly called “ joints,” each of which has to 
some extent an independent individuality. Each joint has 
its own set of sexual organs, both male and female, and may 
be regarded as a bud thrown off by the head. It may, how- 
ever, not be judicious to attach too much weight to this 
example of the tape-worm. Like parasites in general, this 
animal has reached its present position by a process of de- 
generation or retrograde evolution. 
