20 LIVERPOOL BIOLOGICAL SOCIETY. 
the ordinary beach, and is only exposed at the lowest 
spring tides. It is the zone where the great tangled 
brown masses of the oar-weed or Laminaria are found, 
and it is there that marine invertebrate life is to be seen 
in its greatest profusion ; it is there that the competition 
is keenest between allied forms of animals, that the 
struggle for existence is carried on most fiercely; it is there 
probably that evolution is going on most rapidly, there 
that its conditions may most advantageously be studied. 
On turning over a large stone on this region of the 
shore, or when coming suddenly upon a small pool or a little 
cave, the sides of which are clothed with various forms of 
animal life, it is extremely instructive to the evolutionist 
to notice which are the most conspicuous forms, and to 
try to account for their want of any protective colouring 
or attempt at concealment. My experience is that the 
animals which first attract attention are those which move 
rapidly, such as many of the Crustacea and of the Annelids. 
The movements which render these animals conspicuous 
conduce in most cases to their escape from enemies, but it 
is interesting to find that some animals which are able to 
move have actually acquired the habit of lying perfectly 
still so as to escape observation. 
The next most conspicuous animals I find to be the 
pure white calcareous and some of the scarlet and other 
bright-coloured siliceous sponges. Now, these are all of 
them animals which are very completely protected from 
enemies by the numerous sharp- pointed spicules with 
which they are provided. The gleaming white Compound 
Ascidians (Leptoclinwm) may be placed in the same 
category, as they likewise are all richly supplied with sharp- 
pointed spicules. Some of the Polyzoa are also very 
highly coloured and at once attract attention, but they 
seem to be all forms which are either well protected from 

