IN HIGHER INVERTEBRATES 53 
tance; but were there no profiting by experience most of the shots 
would go wide. Parental care might be here symbolized by sup- 
posing the raw beginner protected and instructed by an expert 
shot until the necessary experience had been acquired. 
We do not know how far down in the scale of animal life some 
sort of consciousness exists, but the dawn of intelligence is marked 
by the appearance of what Lloyd Morgan calls “effective con- 
sciousness ”, z.é. a realization of existence which enables more or 
less successful adjustments to a changing environment. 
In ourselves we find Intelligence reinforced by Reason, the 
“ideational stage” in mental evolution, where actions depend upon 
motive, instead of being due to mere impulse dictating certain 
sorts of behaviour “on the spur of the moment”. It involves 
appreciation of abstract ideas with powers of reflection and deliber- 
ation, leading us to trace the relations between cause and effect, 
and to construct ideals of existence by which our conduct is more 
or less regulated. The dim beginnings of Reason are probably 
to be found among the higher animals, but the body of facts with 
which we are at present acquainted is far too small to justify 
positive statements or wide-sweeping generalizations. 
INSTINCT AND INTELLIGENCE IN HIGHER INVERTE- 
BRATES (INVERTEBRATA) 
The most instructive cases so far investigated are to be found 
among Insects (Insecta) and Molluscs (Mollusca), and it will be 
enough for our present purpose to briefly describe a few of these. 
InsTINCT AND INTELLIGENCE 1N InsEcTs (INSEcTA).—A good 
example of the stereotyped nature of complex instincts is given 
by Fabre (in Souvenirs entomologigues) in his account of one of 
the Mason-Bees (Chalicodoma muraria) native to South Europe. 
The female makes a nest consisting of nine or ten cells placed one 
on top of the other, using cement made of a mixture of earth and 
saliva, to which little stones are added. After each cell is built 
it is stored with honey and pollen, after which an egg is laid in it, 
anda roof is added. The entire series is then thickly covered with 
cement till the nest assumes a hemispherical form. The three 
operations of building, storing, and egg-laying which take place 
in regard to each cell follow one another with automatic regularity, 
and there is no harking back to an earlier stage. For conditions 
