Crabs of the British Isles (29,193 t), various swimming crabs (3,180 t), the spider crab "Maja squinado" (1,565 t), the shore crab or green crab "Carcinus maenas" (553 t) and the velvet crab "Necora puber" (193 t). Around 77% of the catch is landed in the United Kingdom, 19% in Ireland, 4% in the Channel Islands, and 1% in the Isle of Man. 62 species have been directly observed in the waters of the British Isles: Three deep-water species have also been recorded near the British Isles, and are likely to occur in the area. These are: Crabs of the British Isles Around 65 species
Stone circles in the British Isles and Brittany the British Isles, architectural changes were made to the style of chambered tomb, which may have been a forerunner of the later circular design of the stone rings. In the later Clyde tombs of south-western Scotland and the court-cairns of northern Ireland, crescent-shaped forecourts were constructed inside the tombs. This would have enabled more people to enter the tomb and take part in any rites there in sunlight. During the Early Neolithic another form of monument was also constructed in the British Isles, now known by archaeologists as causewayed enclosures. These consisted of massive circular ditch-and-bank earthworks. Construction of causewayed