18 NOTICES OF THE MEETINGS (Feb. 14, 
security for the growth of marine plants and animals, presents 
similar features, and can be subdivided into a series of corresponding 
sub-regions ; through all of which the common limpet (Patella vul- 
gata) ranges, giving a character to the entire belt. Each of these 
sub-regions has its own characteristic animals and plants. Thus the 
highest is constantly characterised by the presence of the periwinkle 
Littorina rudis, (and on our Western shores, Littorina neritoides,) along 
with the sea-weed Fucus canaliculatus. The second sub-region is 
marked by the sea-weed Lichina and the common mussel (Mytilus 
edulis). In common with the third sub-region it almost always 
presents rocks thickly encrusted with barnacles ; so that where our 
shores are steep, a broad white band, entirely composed of these 
shell-fish, may be seen when the tide is out, marking the middle 
space so conspicuously as to be visible froma great distance. In the 
third sub-region the commonest form of wrack or kelp (Fucus articu- 
latus) prevails, and the large periwinkle (Littorina littorea) with 
Purpura Capillus are dominant and abundant. In the fourth and 
lowest sub-region the Fucus just mentioned gives way for another 
species, the Fucus serratus ; and in like manner the shells are replaced 
by a fresh Littorina (littoralis) and peculiar Trochi. 
Once below low-water mark the periwinkles become rare, or dis- 
appear, and the Fuci are replaced by the gigantic sea-weeds known 
popularly as tangles (species of Laminaria, Alaria, Sc.) among 
which live myriads of peculiar forms of animals and lesser plants. 
The genus Lacuna among shell-fish is especially characteristic of this 
zone. In sandy places the Zostera or grass-wrack replaces the 
Laminaria. The Laminarian Zone extends to a depth of about fif- 
teen fathoms, but in its lowest part the greater sea-weeds are com- 
paratively few, and more usually the prevailing plant is the curious 
coral-like vegetable called Nullipore. 
From 15 to 50 or more fathoms we find a zone prolific in peculiar 
forms of animal life, but from which conspicuous vegetables seem 
almost entirely banished. The majority of its inhabitants are pre- 
dacious. Many of our larger fishes belong to this region, to which, 
on account of the plant-like zoophytes abounding in it, the name of 
Corau.ine Zone has been applied. The majority of the rarer shell- 
fish of our seas have been procured from this region. 
Below 50 fathoms is the Recion or Drrp-sea Corats, so styled 
because hard and strong true corals of considerable dimensions are 
found in its depths. | In the British seas it is to be looked for around 
the Zetlands and Hebrides, where many of our most curious animals, 
forms of Zoophytes and Echinoderms, have been drawn up from the 
abysses of the ocean. Its deepest recesses have not as vet been 
examined. Intothis region we find that not a few species extend their 
range from the higher zones. When they do so they often change 
their aspect, especially so far as colour is concerned, losing bright- 
ness of hue and becoming dull-coloured or even colourless. In 
the lower zones it is the association of species rather than the 
