sentences:  In 1889, William Bateson observed in detail the way that decorator crabs fix materials on their backs.He noted that "[t]he whole proceeding is most human and purposeful", and that if a "Stenorhynchus" crab is cleaned, it will ""immediately" begin to clothe itself again with the same care and precision as before".In his "The Colours of Animals" (1890), Edward Bagnall Poulton classified protective animal coloration into types such as warning colours and protective mimicry.