Broader definitions of chemicals or chemical substances can be found, for example: the term 'chemical substance' means any organic or inorganic substance of a particular molecular identity, including â (i) any combination of such substances occurring in whole or in part as a result of a chemical reaction or occurring in nature.
The major groups of worms include various species of flatworm, annelid, ribbon worm, spiny-headed worm, and aschelminth. Worms typically have an elongated, tubelike body, usually rather cylindrical, flattened, or leaflike in shape and often without appendages.
Round worms, or nematodes, in larval form are found in the guts and in the flesh of many fish marketed in the United Kingdom; two kinds predominate, the 'cod worm' and the 'herring worm'. The 'cod worm', which is often found in cod, is also found in many other species. Its scientific name is Phocanema decipiens; other outdated scientific names are Porrocaecum decipiens or Terranova decipiens. It grows up to 4 cm long in fish, and varies in colour from creamy white to dark brown.