SPIDER CAN BE FUN FOR ANYONE

[16] On the other hand, in spiders, it occupies just the upper Portion of the abdomen, and blood is discharged in the hemocoel by just one artery that opens within the rear end in the abdomen and by branching arteries that pass through the pedicle and open into various areas of the cephalothorax. As a result spiders have open circulatory units.[thi