Seperti itu pulalah, Darwin dalam bukunya, The Origin of Species, mengakui tidak mungkinnya menjelaskan makhluk dengan teorinya di satu bab yang judulnya ?Difficulties of the Theory Kelemahan-Kelemahan Teori.
Likewise, Darwin in his book, The Origin of Species, admitted the impossibility of explaining these creatures by his theory in a chapter called Difficulties of the Theory.