Scorpions
Scorpions respiratory system contains four pairs of book lungs. The book lungs are shaped like books and are stacks of tissue that t are located in the atrium of the scorpion. The lungs get new air by little slits in the scorpion allowing for gasses to move in and out.
Crabs
Crabs respiratory System uses lungs and gills. Crabs inhale water through nine sets of gills. The water enters through slits in the crab between joints. The water is then circulated throughout the body by the lungs and then exhaled out of the gill.
Spiders
Spiders repiratory system consists of book lungs and a tracheal system. The book lungs fill with haemolymph which helps to diffuse oxygen. There is a opening located in the abdoman and the oxygen diffuses into the haemolymph or directly into the organs or tissues.