environment since nylon is produced from petroleum, and hagfish slime threads could be implanted into bacterium and grown with no harm to the environment. Egg characteristics Mature females usually contain up to 42 eggs. The average is 4 eggs over 5 mm long. Mature black hagfish females often contain various sized groups of eggs—sometimes having three distinct size groups. Contained in a typical gonad might be: one group with eggs from 19 – 22 mm, another group with eggs ranging from 1 – 4 mm, and a third group of eggs less than 1mm long. Ovaries often contain over 200 eggs, each less than 1 mm. Gonad stages The adjacent image shows the various stages of egg development: 1. Eggs in an immature female. All eggs are less than 1 mm long, round, and are present along the length of gonad. 2. Maturing female. Oblong eggs, most less than 5 mm long, with a few longer than 1 mm. 3. Mature ova in developing female. Some eggs are longer than 5 mm. 4. Mature ova in developed female. At both ends of egg, hooks are present. 5. Mature, spent female showing large, empty ovarian capsules (and some oblong eggs). 6. Showing three different size groups of eggs in gonad. Slime Black hagfish produce copious amounts of slime as a defense mechanism. Deep-sea diving equipment is known to have been fouled by large amounts of hagfish slime near the bottom of the ocean, extruded by the eel-like fish when they are alarmed. The slime comprises mature thread cells, up to long that are coiled and thread-like. References External links Images of black hagfish devouring a fish Myxinidae Scavengers Western North American coastal fauna Fish described in 1907