2 ZOOLOGY. 
early observers regarded them as ‘‘ animal flowers ;’’ and in 
consequence of the confused notions originally held in regard 
to them the term Zoophytes has been perpetuated in works 
on systematic zoology. Even at the present day the com- 
pound Hydroids, such as the Sertularia, are gathered and 
pressed as sea-mosses by many persons who are unobservant 
of their peculiarities, and unaware of the complicated anat- 
omy of the little animals filling the different leaf-like cells. 
Sponges until a very late day were regarded by our leading 
zoclogists as plants. The most accomplished naturalists, 
however, find it impossible to separate by any definite lines 
the lowest animals and plants. So-called plants, as Bacte- 
rium, and so-called animals, as Protameba, or certain mo- 
nads, which are simple specks of protoplasm, without gen- 
uine organs, may be referred to either kingdom ; and, in- 
deed, a number of naturalists, notably Haeckel, relegate 
to a neutral kingdom (the Protista) certain low- 
est plants and animals. Even the germs (zo- 
ospores) of monads like Uvella (Fig. 1), and those 
of other flagellate infusoria, may be mistaken 
g for the spores of plants ; indeed, the active fla- 
Fig. 1.—Uv@. gellated spores of plants were described as in- 
la,a flagellate fusoria by Ehrenberg ; and there are certain so- 
infusorian, or 
monad, with called flagellate infusoria so much like low 
two large ci- 
Jia called plants (such as the red snow, or Protococcus), 
Gredily tae in the form, deportment, mode of reproduc- 
cs tion, and appearance of the spores, that even 
now it is possible that certain organisms placed among them 
are plants. It is only by a study of the connecting links 
between these lowest organisms leading up to what are un- 
doubted animals or plants that we are enabled to refer these 
beings to their proper kingdom. 
Asa rule, plants have no special organs of digestion or 
circulation, and nothing approaching to a nervous system. 
Most plants absorb inorganic food, such as carbonic acid 
gas, water, nitrate of ammonia, and some phosphates, silica, 
etc. ; all of these substances being taken up in minute quan- 
tities. Low fungi live on dead animal matter, and promote 
the process of putrefaction and decay, but the food of these 
