<P> Coeloms developed in triploblasts but were subsequently lost in several lineages . The lack of a coelom is correlated with a reduction in body size . Coelom is sometimes incorrectly used to refer to any developed digestive tract . Some organisms may not possess a coelom or may have a false coelom ( pseudocoelom ) . Animals having coeloms are called coelomates , and those without are called acoelomates . There are also subtypes of coelom : </P>
<P> Coeloms developed in triploblasts but were subsequently lost in several lineages . The lack of a coelom is correlated with a reduction in body size . Coelom is sometimes incorrectly used to refer to any developed digestive tract . Some organisms may not possess a coelom or may have a false coelom ( pseudocoelom ) . Animals having coeloms are called coelomates , and those without are called acoelomates . There are also subtypes of coelom : </P>
an animal that lacks a coelom or body cavity
an animal that lacks a coelom or body cavity
acoelomates
acoelomates