id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
chapter_013		chapter_013			.txt	text/plain	14903	382	43	Extinction has only separated groups: it has by no means made them; for if every form which has ever lived on this earth were suddenly to reappear, though it would be quite impossible to give definitions by which each group could be distinguished from other groups, as all would blend together by steps as fine as those between the finest existing varieties, nevertheless a natural classification, or at least a natural arrangement, would be possible. And in some whole groups of animals and in certain members of other groups, the embryo does not at any period differ widely from the {442} adult: thus Owen has remarked in regard to cuttle-fish, there is no metamorphosis; the cephalopodic character is manifested long before the parts of the embryo are completed; and again in spiders, there is nothing worthy to be called a metamorphosis.	cache/chapter_013.txt	txt/chapter_013.txt
