Wood-decay fungus fungi of certain types remove cellulose compounds from wood and hence the wood becomes brown colour. Brown rot in a dry, crumbly condition is sometimes incorrectly referred to as "dry rot" in general. The term "brown rot" replaced the general use of the term "dry rot", as wood must be damp to decay, although it may become dry later. Dry rot is a generic name for certain species of brown-rot fungi. Brown-rot fungi of particular economic importance include "Serpula lacrymans" (true dry rot), "Fibroporia vaillantii" (mine fungus), and "Coniophora puteana" (cellar fungus), which may attack timber in buildings. Other brown-rot
Serpula vermicularis tube is fabricated by the glandular ventral shields on the other thoracic segments, where calcium is mixed with an organic secretion to make a paste. This is formed into shape by a collar found just behind the first segment, the prostomium. "Serpula vermicularis" is a filter feeder and extends its radioles to catch phytoplankton and detritus. The radioles also act as gills. Blood is pumped in and out of these with the flow direction alternating in a single set of vessels. The blood is then pumped through a ventral blood vessel to the tip of the abdomen before returning through