They are terrestrial, but require a certain amount of 

 moisture. On the other hand, they are unahle io 

 withstand prolonged immersion in sea-water, and still 

 less in fresh Avater. 



They are found just above hig-h-water mark in a 

 7Ame of varying- width. The heig-ht of their habitat above 

 hig-h-water mark seems to depend on the nature of their 

 surroundings, which is varied. The g-reatest number are 

 found in deep narrow crevices in the rocks immediately 

 above high water. Here they can l)e found in large numbers 

 packed closely together. They also abound in crevices 

 on the side of a qii^j, 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 crevices 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 doAvn to sea 

 level to feed. Contrary to the usual rule, the majoritv of 

 individuals found at this high level were females. I 

 found large numbers of young individuals under rocks 

 betAveen tide marks, and none at the high level, these 

 females probably go do\A-n to the sea level to liberate the* 

 yonng from their brood-ponches. 



The colour vai-ies from a dark ffrevish yreen to a 



