68 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
They are terrestrial, but require a certain amount of 
moisture. On the other hand, they are unable to 
withstand prolonged immersion in sea-water, and still 
less in fresh water. 
They are found just above high-water mark in a 
zone of varying width. The height of their habitat above 
high-water mark seems to depend on the nature of their 
surroundings, which is varied. The greatest number are 
found in deep narrow crevices in the rocks immediately 
above high water. Here they can be found in large numbers 
packed closely together. They also abound in crevices 
on the side of a quay, hence their name, ‘ quay-louse’ or 
‘quay-lowders.’ They are also known as ‘ sea-carpenters,’ 
‘carpenter’ being a local name of the wood-louse. They 
can be found between the wooden piles of a pier or under 
the loose stones and rubbish cast up by the tide, which have 
accumulated in small dark holes. The highest level is 
attained by those specimens which live in the loose clay 
and shale forming the cliffs on many parts of our 
coast, but the specimens living in these conditions do not 
attain the size of those living lower down in the rock 
crevices, and are generally of a darker colour. 
In St. Kilda, I have found them in the erevices of the 
boulders on the top of a hill over 450 feet above sea-level. 
This high altitude may be explained by the fact that the 
sea spray often reaches that height. It is extremely 
improbable, however, that the animals go down to sea 
level to feed. Contrary to the usual rule, the majority of 
individuals found at this high level were females. I 
found large numbers of young individuals under rocks 
between tide marks, and none at the high level, these 
females probably go down to the sea level to liberate the 
young from their brood-pouches. 
The colour varies from a dark greyish green to a 
