Longitudinal-section of a crayfish, showing digestive, circulatory, reproductive, excretory, and nervous…
Dorsal view of internal structures of earthworm after cutting through the dorsal wall lengthwise and…
Mechanism for opening and shutting a clam shell, note the internal and external hinge ligament..
Cross section of the body of a clam, through the heart. Arrows indicate water current through the gills.
Cross section of the body of a clam, through the posterior adductor muscles. Arrows indicate water current…
Young clam, still within the egg membrane. m, adductor muscle; t, hooks by which it attaches itself…