Dry rot be more distinctive in these species than water translocation. Water translocated in this fashion carries nutrients to the extremities of the organism; not, as is sometimes inferred, to simply render dry timber wet enough to attack. Coggins goes into more detail about water movement in "Serpula lacrymans". The perpetual saturation of wood with water also inhibits dry rot, as does perpetual dryness. "Dry rot" would appear to be a paradoxical term seemingly indicating decay of a substance by a fungus without the presence of water. However, its historical usage dates back to the distinction between decay of cured wood in
Serpula tidal fashion. In the central circulatory system, the blood moves anteriorly from the tip of the abdomen to the front of the thorax through a sinus enveloping the alimentary canal, and posteriorly through a ventral blood vessel. The ventral vessel and the sinus communicate with each other by segmentally arranged ring vessels, and by a dorsal vessel, a transverse vessel, and a pair of circumesophageal vessels situated at the anterior end of the thorax. The dorsal vessel in some of the larger serpulids, like "Serpula", possesses a valve and a muscular sphincter, probably to prevent backflow of blood from the