Do Mollusks Have a Circulatory System

Mollusks possess an open circulatory system in which body fluid (hemolymph) is transported largely within sinuses devoid of distinct epithelial walls. The posteriodorsal heart enclosed in a pericardium typically consists of a ventricle and two posterior auricles.

Do mollusks have a true circulatory system?

All mollusks except those in the class Cephalopoda have an open circulatory system. In an open circulatory system, blood is not contained entirely in enclosed blood vessels. The heart pumps blood through blood vessels that lead from the gills into body cavities called hemocoels.

Do mollusks have respiratory system?

Basically all molluscs breathe by gills that are called ctenidia (comb-gills) because of their comb-like shape. In terrestrial molluscs this respiration organ is reduced, but still respiration takes place in the pallial cavity. That is why it is also called the snail’s respiratory cavity.