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 vigorous pumping movements of the abdomen and also by the activity of the ciliary tracts. The well-developed longitudinal muscles of the body wall of serpulids lack a special blood supply. The body surface in the larger serpulids, like "Serpula", has a rich blood supply, and the water in contact with this surface is constantly renewed. It seems probable that the outer body surface of serpulids serves as a respiratory membrane, supplying oxygen to the underlying muscles by diffusion. The biochemistry of the blood of "Serpula" is especially unusual in that the blood contains not only hemoglobin, but also chlorocruorin. While