CHAPTER XI. 
CONCLUDING OBSERVATIONS. 
Before taking the last step, before alluding to the 
existence of a group more comprehensive than that of 
animals, it may be wetl to state that I am perfectly aware 
how dangerous is the ground on which I am about to tread. 
Hitherto my conclusions have been drawn from facts 
within the reach of every enquirer, but now the speculative 
must be largely mingled with the demonstrable, and the 
suggestions must bear the character of hypotheses. Under 
these circumstances I would fain appeal to the candour 
of my readers, and, however different their views of this 
general system may be from mine, I solicit them to con¬ 
sider that the question at issue will be merely between 
one hypothesis and another, and that arguments, which in 
their opinion may prove my hypothesis to be unsound, 
cannot shake the stability of anterior conclusions deduced 
solely from phenomena. 
Although I feel perfectly convinced that the animal 
kingdom is but a portion of some other assemblage still 
more vast,—'although I feel assured that no argument will 
ever be adduced to alter this conviction,—yet when I seek 
to ascertain the exact contents of that assemblage, and 
