Jeffreys himself fell under its spell, exclaiming, "I do not know any con chological study more interesting and important, and at the same time more difficult, than that of the Teredo." Let us take a closer look at its anatomy. The clamlike creature has a bivalve shell that functions as a tool, the rough, ridged valve surfaces being used for boring and scraping. These ridges or "dentricles" are what РИПУ mistook for teeth. It also has a muscular foot that permits crawling over surfaces and acts as a suction cup, holding the shell in place during bur rowing. The creature's breathing siphons remain at the surface of the d taking in water and oxygen. Once attached to a piece of wood, the ' rts to turn into a proper shipworm-a metamorphosis, Jeffreys larva starts that is "not less wonderful than that which takes place in the assures i > insect, or polyp" The adult form has a soft, almost gelatinous body d deposits a whitish, calcareous lining on its tunnel walls to protect its gentle flesh. The shipworm requires three main conditions for life: proper temper ture salinity, and the presence of wood. A habitue of the sea, it does not fare well in freshwater lakes or inlets. It requires salinities ranging from normal sea water-averaging about 35 parts per thousand-to as low as 9 parts per thousand, according to Dr. Ruth Turner, the Harvard marine biologist who recently passed away at eightyfive, after devoting her life to studying the teredo. (Her obituary says she was affectionately called "Lady Wormwood," she scubadived until she was well into her seventies, and she never married, giving her heart, perhaps, to the shipworm.) Sellius, who experimented by thrusting shipworms into beer, rainwater, and milk, discovered, as one might predict, that they did not prosper. They dislike cold, breed in warm weather, and, when placed in a jar, invariably seek the sunny side. They also prefer shallow water, and are found most often around or slightly above the mud line. Though originally associated with one or another region, as a sort of local curse, they can be dispersed considerable distances by ocean currents, and may wash up anywhere on the globe, provided they have secured adequate ligneous transportation. Their palates, well described by Sigerfoos (1908), are peculiar, tubelike structures that extrude siphons, which take in food and considerable amounts of water, which in turn help reduce the wood to a flocculent mass. These palates look like pieces of appendix, or asparagus stalks, or bent peruses, hence the misnomer "worm." They soon outgrow the shell, which апУ case is too frail to possess much protective function. If the shell is thin compared to that of other bivalves, it is perhaps because the shipworm finds all the protection it needs by lodging in a piece of wood. Once it has Sned its hiding place, it escapes assault from other predators. Should another shipworm enter the abode, the first will make way. A single two .