perivisceral
Adjective
Meaning
Around the viscera; as, the perivisceral cavity.
Source: Webster's dictionaryExamples
Aside from the water vascular system, echinoderms have a haemal coelom (or haemal system, the "haemal" being a misnomer), a perivisceral coelom, a gonadal coelom and often also a perihaemal coelom (or perihaemal system).
This pumps the blood from the front end of the heart into the perivisceral sinus containing the organs.