type of fertilization in which eggs and sperm are both released into water; fertilization occurs outside the animal's body.
method in which food particles are filtered from water as it passes by or through some part of the organism.
in cnidarians, a large cavity in which digestion takes place.
individual animal that can produce both eggs and sperm; increases the likelihood of fertilization in sessile or slow-moving animals.
type of fertilization in which eggs remain inside the female's body and sperm are carried to the eggs by water or other fluid.
is the stage with a body shaped like an umbrella with tentacles hanging downward.
in cnidarians, a capsule that contains a coiled, threadlike tube that may be sticky, barbed, or contain poisons; used in capturing and digestion prey.
simple netlike nervous system in cnidarians that conducts nerve impulses from all parts of the cnidarian's body; impulses are not controlled by a central nervous center.
in the life cycle of cnidarians, the stage where the body is tube-shaped, with a mouth surrounded by tentacles.
in planarians, the tube like, muscular organ that extends from the mouth; aids in feeding and digestion.
detachable section of a tapeworm that contains muscles, nerves, flame cells, and reproductive organs.
replacement or regrowth of missing body parts by mitosis.
knob-shaped head of a tapeworm.