Injection of killed microorganisms can induce immunity to subsequent infection. Heat transfer . Haemolymph is involved in transfer of heat from one body region to another. General pattern of blood circulation. Blood enters heart through pores called ostia , and is directed anteriorly by peristaltic contractions .
Blood returns to general circulation from the head.
With the aid of undulatory movements from the diaphragms that partially separate the various body parts, the accessory pulsatile structures and visceral and body movements, blood circulates through the body cavities and appendages.