Pila is a amphibian .When it is in water, it will perform branchial respiration with the help of gill. When it is on land it will perform pulmonary respiration with the help of pulmonary chamber.
Branchial respiration :
When pila is in water it will perform respiration with gill or ctenidium.
Ctenidium : It is present in the branchial chamber. It ismonopectinategill. On its axis lamellae are present on one side only. It looks like a comb.
Process of branchial respiration :
From left pseudepipodium water enters into branchial chamber. This water is tested by ospharadium. The water will travel over the gill. The blood present in the gill will absorb 02 from this water and liberate C02The used up water will go out through right pseudopipodium.
Pulmonary respiration :
When pila lives on land it will perform pulmonary respiration. The wall of pulmonary sac is supplied with blood capillaries. Air enters into the pulmonary sac with the help of left pseudepipodium which becomes a tube like structure. After exchange of gases in the pulmonary sac. the spent air is sent out through an opening present on the pulmonary sac »