Dissepiments


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Dissepiments

 

the slender transverse partitions in the coelom of metameric invertebrate animals, such as segmented worms. Dissepiments form by the joining of the adjacent walls of paired coelomic cavities arranged one behind the other. Contraction of the muscles of the dissepiments and of the musculocutaneous sac causes pressure changes in the cavity fluid. Dissepiments are most pronounced in polychaete and oligochaete worms, and they are absent in leeches.

References in periodicals archive ?
Propora tubulata has the most distinct density bands among heliolitids and, therefore, skeletal elements, such as corallite wall, coenenchymal dissepiments, and septal spines, vary from thin to thick (Table 4).
Several morphological novelties such as septofossulae (Ullernelasma), dissepiments (Paliphyllum, Strombodes), and colonial forms (Cyathophylloides, Palaeophyllum), etc., appeared in the Hirnantian (t.s.