All about Arachnids for your smartphone, your iPhone or any phone. The body has two regions or tagmas more or less distinct, the prosoma (or cephalothorax) and the opisthosoma (or abdomen). Circulation is open, as in all arthropods. Excretion, as is typical of animals normally not drink and sometimes grow in arid environments produces a very concentrated or dried urine, rich in guanine and uric acid (are thus uricotélicos). Excretion organs are Malpighian tubules, which empty into the intestine or coxal glands, making it at the base of the legs.