[{155}] In the Origin, Ed. i. p. 438, vi. p. 602, the author, referring to the expressions used by naturalists in regard to morphology and metamorphosis, says “On my view these terms may be used literally.”
[{156}] See Origin, Ed. i. p. 439, vi. p. 605.
[{157}] In the Origin, Ed. i. p. 440, vi. p. 606, the author argues that the “loop-like course of the arteries” in the vertebrate embryo has no direct relation to the conditions of existence.
[{158}] The following passages are written across the page:—“They pass through the same phases, but some, generally called the higher groups, are further metamorphosed.
? Degradation and complication? no tendency to perfection.
? Justly argued against Lamarck?”
[{159}] An almost identical passage occurs in the Origin, Ed. i. p. 440, vi. p. 606.
[{160}] The following: “Deaths of brothers «when» old by same peculiar disease” which is written between the lines seems to have been a memorandum which is expanded a few lines lower. I believe the case of the brothers came from Dr R. W. Darwin.
[{161}] See the discussion to this effect in the Origin, Ed. i. pp. 443-4, vi. p. 610. The author there makes the distinction between a cause affecting the germ-cell and the reaction occurring at a late period of life.
[{162}] Possibly the sentence was meant to end “is not visible till then.”