Chordates are the most commonly known phylum on the Earth because it contains vertebrates and humans. All of these animals share similar characteristics in terms of structure and muscle composition. For example, all of these animals have bilateral symmetry or the quality of having symmetry when divided on a certain plane into two equal halves. Also, chordates contain a hollow nerve cord called the dorsal and a notochord that runs the length of the body.
The muscular systems of these animals share common parts as well. All chordates have a post-anal tail in either the embryonic development or one that is physically visible and segmented muscles. The muscles usually work together with the external skeletal system to form a system called the musculoskeletal system. This system allows for more efficient and easier movement.
http://animaldiversity.ummz.umich.edu/accounts/Chordata/
http://muscularsystemashe.weebly.com/chordata.html
http://www.ucmp.berkeley.edu/chordata/chordata.html
The muscular systems of these animals share common parts as well. All chordates have a post-anal tail in either the embryonic development or one that is physically visible and segmented muscles. The muscles usually work together with the external skeletal system to form a system called the musculoskeletal system. This system allows for more efficient and easier movement.
http://animaldiversity.ummz.umich.edu/accounts/Chordata/
http://muscularsystemashe.weebly.com/chordata.html
http://www.ucmp.berkeley.edu/chordata/chordata.html