Annelida
There are over 1 million different species of Annelids today, these can be found on both terrestrial and marine style environments. All of these annelids are also bilaterally symmetrical, meaning that they have the body vertically divided between their left and right side with each one being the same. Various types of annelids possess many significant abilities such as breathing through their skin, but may have many drawbacks such as not having a set of eyes or having quick, extensive mobility.
The Annelida has an interesting cardiovascular system that varies within the organisms of the phylum. The blood within these organisms often has hemoglobin in it, it also usually is a closed cardiovascular system with blood vessels that are very well developed, it can also have a circulatory system that is partially open with blood mixing near the cavity in the body. Some other vessels within certain organsims also serves as its heart.
The Annelida has an interesting cardiovascular system that varies within the organisms of the phylum. The blood within these organisms often has hemoglobin in it, it also usually is a closed cardiovascular system with blood vessels that are very well developed, it can also have a circulatory system that is partially open with blood mixing near the cavity in the body. Some other vessels within certain organsims also serves as its heart.