Annelida Phylum
All annelids have a closed circulatory system, which means that blood circulates only within the blood vessels and through the heart. Some species that consist of the Annelida phylum are earthworms, polychaetes, and lugworms. Like I said before, all of these species have a closed circulatory system.
-An earthworm is a complex organism that has a circulatory system, which means that its blood is confined to blood vessels and its blood is recirculated so its blood is used to its maximum. Earthworms don’t have lungs or grills but its body its body absorbs oxygen from the soil. The oxygen is taken in by the earthworm’s dorsal blood vessel. Due to the fact that earthworms receive oxygen through moist soil, it will eventually die if the soil becomes too dry or too wet.
http://www.angelfire.com/de2/atoy/cir.htm
-Polychaetes are often described as elongated worms, also known as “bristle worms”. Polychaetes have a closed circulatory system and many of these worms have distinct gills. Their gills are adapted as highly vascularized parts of the parapodia and their circulatory systems are well developed with two vessels carrying blood in the dorsal vessel and ventral vessel directions along the full body of the entire worm.
http://eolspecies.lifedesks.org/pages/48688
-Lugworms are a type of segmented worm, also known as the “sandworm”. The reason why the lugworm is also referred to as the “sandworm” is because they live underground, beneath sand. They don’t usually come above ground, so if you do consider it a rare event. Lugworms contain a closed circulatory system and it receives its oxygen from the sand, like the earthworm does from the soil. (http://www.wisegeek.com/what-are-segmented-worms.htm
-An earthworm is a complex organism that has a circulatory system, which means that its blood is confined to blood vessels and its blood is recirculated so its blood is used to its maximum. Earthworms don’t have lungs or grills but its body its body absorbs oxygen from the soil. The oxygen is taken in by the earthworm’s dorsal blood vessel. Due to the fact that earthworms receive oxygen through moist soil, it will eventually die if the soil becomes too dry or too wet.
http://www.angelfire.com/de2/atoy/cir.htm
-Polychaetes are often described as elongated worms, also known as “bristle worms”. Polychaetes have a closed circulatory system and many of these worms have distinct gills. Their gills are adapted as highly vascularized parts of the parapodia and their circulatory systems are well developed with two vessels carrying blood in the dorsal vessel and ventral vessel directions along the full body of the entire worm.
http://eolspecies.lifedesks.org/pages/48688
-Lugworms are a type of segmented worm, also known as the “sandworm”. The reason why the lugworm is also referred to as the “sandworm” is because they live underground, beneath sand. They don’t usually come above ground, so if you do consider it a rare event. Lugworms contain a closed circulatory system and it receives its oxygen from the sand, like the earthworm does from the soil. (http://www.wisegeek.com/what-are-segmented-worms.htm