Nature has made the Proteus a true creature of darkness—perhaps more so than any land-dwelling worm. As described by the late Dr. Austin H. Clark, Smithsonian Institution biologist: “The Proteus is almost as sensitive to light as a photographic plate. The light of a candle at some distance is strong enough to make it restless. If it is kept in a place from which light is not entirely excluded its white skin turns cloudy with the appearance of gray patches, and if it is kept in an ordinary lighted room it eventually turns jet-black.” Proteus is eyeless. It seems feeble and helpless. Yet it is well adapted for its life in dark caves. Most of the time it lies at the bottoms of pools, completely motionless. But, says Dr. Clark, “any small living thing in the water attracts its immediate attention. It advances toward it, snaps it up and eats it. It seems to be guided mostly by the movements of its victims in the water, possibly also by a sense of smell. In the deep caves food naturally is scarce and the animal often must go for a considerable time without anything to eat. In captivity individuals have lived for months with no food at all.” Ghostly dweller in the everlasting darkness of limestone caves in the Ozarks is the Typhlotrition, a blind, wormlike white salamander of the same general family as Proteus. It is a long, slender, nearly transparent creature, which has evolved a long way towards complete blindness. The newly hatched young have functioning eyes but these degenerate in the adult so that it does not seem able to discriminate light from darkness. It is barely able to stand on its thin, barely visible legs. It lives on blind crustaceans and apparently spends most of its life crawling through the small, underground streams which seep through the limestone rocks of the Ozark foothills. A quite similar creature of the same family was discovered in 1896 in Texas during the boring of an artesian well. A subterranean stream was struck at a depth of about 200 feet. From it this white, wormlike creature was shot out, together with some remarkable crab-like animals. A single specimen of a similar animal since has been found in Georgia. Both these organisms are more wormlike even than Proteus. They apparently have lived for milleniums in streams flowing hundreds of feet below the earth. Both, it has been conjectured, are larval forms of a well-known salamander of surface waters, which have become permanent larvae. They have lost the ability to undergo metamorphosis, like the change of a tadpole into a frog or a caterpillar into a butterfly.