sentences:  Ex ungue leonem, "from its claw [we can know] the lion," is a similar phrase, noted in "Benet's Reader's Encyclopedia" 1948.The principle was raised to an axiom of biology by D'Arcy Wentworth Thompson, in "On Growth and Form", 1917; it has found dependable use in paleontology, where the measurements of a fossil jawbone or a single vertebra, offer a close approximation of the size of a long-extinct animal, in cases where comparable animals are already known.The studies of proportionality in biology are pursued in the fields of morphogenesis, biophysics and biostatistics.