46 
which, in the present state of our knowledge, appeared to him to be 
disputed or doubtful. We all knew the difficulty that existed, in 
the lower forms of animal and vegetable life, in distinguishing the 
one from the other—a difficulty which did not appear to decrease as 
our knowledge increased. So much was the difficulty felt that one 
able zoologist (Dr. Haeckel) had proposed to form an intermediate 
kingdom, in which to place all organisms of a doubtful character. 
Professor Rolleston remarked that ‘‘ there are organisms which, at one 
period of their life, exhibit an aggregate of phenomena such as to 
justify us in speaking of them as animals ; while at another they ap- 
pear to be as distinctly vegetable.” It was only within the last few 
years that the position of two well-known objects—Volvox and the 
Sponge—had been determined. The former, from its power of 
locomotion, was ranked by the earlier observers with the microscope 
among the infusorial animalcule, whilst the latter, from its want of 
those powers, and from its habit of fixedness, was placed in the 
vegetable kingdom. But now the Volvox was considered to be a 
low form of vegetable organism, while the sponge was looked upon 
as one of the Protozoa, or first form of animal life. Then, some 
insects resembled the leaves on which they fed or among which 
they lived; others were like little bits of stick or twigs. Other 
animals were white in winter; the red grouse was assimilated to 
the colour of heather, the black grouse to that of peaty earth, and so 
on. Butif these disguises were intended, as stated, for the pro- 
tection of these creatures, how was it that we found so very few, 
comparatively speaking, thus protected ? Why should one tribe or 
family be thus favoured, and numberless others left to take care of 
themselves as best they could? Whilst admitting that certain 
animals were thus protected, he could not help thinking that the 
so-called ‘‘ disguises” were accidental, by which he meant that in 
the immense varieties of forms and colours that we met with in the 
field of Nature, some animals must of necessity bear a resemblance 
to some vegetable or other object in colour or shape, so that the 
term ‘‘ disguises’ was not correct, inasmuch as it implied a power 
in those animals which they did not possess. Of the half-dozen 
disputed or undecided points, Mr. Simpson first alluded to the air 
or swim bladder in fishes, which he said was an organ, the function 
and action of which had by no means been clearly ascertained. 
Having quoted from the descriptions of this organ by several known 
authorities, Mr. Simpson said it was evident that the bladder was 
present in some fish-and absent in others whose habits and 
habitats seem to be alike. Another question which it appeared 
to him was not thoroughly understood was, the power which 
some of the class of reptiles had, in common with other of 
the lower order of animals, of throwing off portions of their 
bodies. The word ‘‘ power” was the term usually adopted, 
