[{83}] As already pointed out, this is the important principle investigated in the author’s Cross and Self-Fertilisation. Professor Bateson has suggested to me that the experiments should be repeated with gametically pure individuals.
[{84}] In the Origin a chapter is given up to “difficulties on theory”: the discussion in the present essay seems slight even when it is remembered how small a space is here available. For Tibia &c. see p. 48.
[{85}] This may be interpreted “The general structure of a bat is the same as that of non-flying mammals.”
[{86}] That is truly winged fish.
[{87}] The terrestrial woodpecker of S. America formed the subject of a paper by Darwin, Proc. Zool. Soc., 1870. See Life and Letters, vol. iii. p. 153.
[{88}] The same proviso occurs in the Origin, Ed. i. p. 207, vi. p. 319.
[{89}] The tameness of the birds in the Galapagos is described in the Journal of Researches (1860), p. 398. Dogs and rabbits are probably mentioned as cases in which the hereditary fear of man has been lost. In the 1844 MS. the author states that the Cuban feral dog shows great natural wildness, even when caught quite young.
[{90}] In the Origin, Ed. i. p. 207, vi. p. 319, he refuses to define instinct. For Lord Brougham’s definition see his Dissertations on Subjects of Science etc., 1839, p. 27.
[{91}] See James Hogg (the Ettrick Shepherd), Works, 1865, Tales and Sketches, p. 403.
[{92}] This refers to the tailor-bird making use of manufactured thread supplied to it, instead of thread twisted by itself.