Phylum Nemertea & Chaetognatha 1

Phylum Nemertea & Phylum Chaetognatha

Ribbon Worms

Arrow Worms

Phylum Nemertea & Chaetognatha 2

Phylum Chaetognatha (Arrow Worms)

Defining Characteristics– A series of curved

chitinous grasping spines on both sides of the head, for seizing prey

– Lateral stabilizing fins

Phylum Nemertea & Chaetognatha 4

Chaetognaths Habits

Living Chaetognaths are almost invisible in the water

Possess two eyes that are useful for sensing motion and light intensity

Phylum Chaetognatha 5

Chaetognatha Feeding

A prey item is sensed by cilia along the body

Feed on copepods, larval crustaceans, young fish and each other

Can occur in very high concentrations several hundred per cubic meter

Can have substantial effects on eggs and larvae some of which are commercially important

Phylum Nemertea & Chaetognatha 6

Reproduction