44 LIVERPOOL BIOLOGICAL SOCIETY. 
upon the fauna and flora of a region; and Professor 
Edward Forbes, in his posthumous work on the “ Natural 
History of the European Seas,” pointed out that the sea 
bottom explored by the naturalist might be conveniently 
divided into four great zones, each inhabited by particular 
sets of animals. These are: (1) the Littoral zone, or the 
area between high and low-water marks. The animals 
and plants are here, of course, under very peculiar con- 
ditions, being for a part of their lives submerged in the sea, 
while for another part they are exposed to the air, to the 
sunlight, to extremes of heat and cold, to the washing of 
rain, or it may be to the pelting of snow. Next comes 
(2) the Laminarian zone, which extends from low-water 
mark downwards to a depth of ten or fifteen fathoms. 
This is pre-eminently the region of sea-weeds and of 
abundant animal life. Here, amongst the great tangled 
masses of the shiny brown Laminaria or oarweed, we find 
a profusion of nearly all forms of marine life, and here 
occur many of those instances of protective colouring and 
mimicry which prove such interesting problems to the 
evolutionist. This is the region the upper edge of which 
is just exposed at extreme low water of spring tides, and 
at such times it yields a rich harvest to the collector. — 
Following the Laminarian zone comes (3) the Coralline 
zone, or region of zoophytes, formerly known as “coral- 
lines.” This zone extends down, on an average, to a depth 
of thirty fathoms or so; and it is the region in which most 
of the scientific dredging is carried on around our coasts. 
It contains very few sea-weeds, but a large and varied 
assemblage of animals. Lastly comes (4) the zone of 
Deep Sea Corals, whose lower limit Forbes did not fix. 
To these regions must now be added the Abyssal zone, 
made known by the dredgings of the ‘‘ Porcupine,” 
“Challenger,” and other scientific expeditions. 
