MARINE BIOLOGICAL STATION ON PUFFIN ISLAND. 9 



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-w^eeds 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. 



