Circulatory System of Earthworm
The blood vascular system of Pheretima is of closed type. It consists of the blood vessels, hearts, loops, capillaries and the blood glands. Blood: The blood of Pheretima is red coloured due to the presence of a respiratory pigment haemoglobin in it. The haemoglobin is not contained in the corpuscles like the vertebrates but it is found dissolved in the [...]