Byssus

Byssus

 

(1) An excretion of the byssal gland, found in the so-called feet of many bivalve mollusks. Immediately upon expulsion, byssus hardens and forms durable silky filaments by which mollusks fasten themselves to underwater objects. In antiquity a special cloth, vysson, was prepared from the byssus excreted by the large mollusk pinna.

(2) A roe disease of freshwater fish caused by certain fungi of the genera Saprolegnia and Achy la.