Chaetognatha
Arrow Worms
Arrow worms are among the smallest organisms in the animal kingdom. There are about 100 species and all are marine. They are one of the most common and most important members of the plankton. They are almost transparent and are streamlined with fish-like fins and tails. They have eyes, grasping spines and teeth. They are carnivorous and eat the eggs and larvae of fish as well as practically anything else that is small.
The name Chaetognatha means "bristle jaw". This refers to the grasping spines near the mouth. The teeth have neurotoxins that help them kill their prey. They do not have circulatory or respiratory systems and have only a simple nervous system. They have a complete digestive tract and are coelomates.
The name Chaetognatha means "bristle jaw". This refers to the grasping spines near the mouth. The teeth have neurotoxins that help them kill their prey. They do not have circulatory or respiratory systems and have only a simple nervous system. They have a complete digestive tract and are coelomates.