<p><strong>Fig. 3.46.</strong> Cross-sectional diagram of a polychaete annelid worm showing the tube-within-a-tube construction of a true coleom body cavity</p>

Fig. 3.46. Cross-sectional diagram of a polychaete annelid worm showing the tube-within-a-tube construction of a true coleom body cavity

Image courtesy of Hans Hillewaert, Wikimedia Commons