the principle of purposes seems to be best authenticated, i.e. from man, down to the polype, and again from this down to mosses and lichens, and finally to the lowest stage of nature noticeable by us, viz. to crude matter. And so the whole Technic of nature, which is so incomprehensible to us in organised beings that we believe ourselves compelled to think a different principle for it, seems to be derived from matter and its powers according to mechanical laws (like those by which it works in the formation of crystals).

Here it is permissible for the archaeologist of nature to derive from the surviving traces of its oldest revolutions, according to all its mechanism known or supposed by him, that great family of creatures (for so we must represent them if the said thoroughgoing relationship is to have any ground).