1 88 1.] SIR WYVILLE THOMSON. 243 



exception to the term "extreme variation," and challenges 

 Sir Wy ville to name any one who has " said that the evolu- 

 tion of species depends only on natural selection." The letter 

 closes with an imaginary scene between Sir Wyville and a 

 breeder, in which Sir Wyville criticises artificial selection in 

 a somewhat similar manner. The breeder is silent, but on 

 the departure of his critic he is supposed to make use of 

 "emphatic but irreverent language about naturalists." The 

 letter, as originally written, ended with a quotation from 

 Sedgwick on the invulnerability of those who write on what 

 they do not understand, but this was omitted on the advice 

 of a friend, and curiously enough a friend whose combative- 

 ness in the good cause my father had occasionally curbed.] 



C. Darwi?i to G. J. Romanes. 



Down, April 16, 1881. 



My DEAR ROMANES, — My MS. on 'Worms' has been sent 

 to the printers, so I am going to amuse myself by scribbling 

 to you on a few points ; but you must not waste your time 

 in answering at any length this scribble. 



Firstly, your letter on intelligence was very useful to me 

 and I tore up and re-wrote what I sent to you. I have not 

 attempted to define intelligence ; but have quoted your 

 remarks on experience, and have shown how far they apply 

 to worms. It seems to me that they must be said to work 

 with some intelligence, anyhow they are not guided by a 

 blind instinct. 



Secondly, I was greatly interested by the abstract in 

 1 Nature ' of your work on Echinoderms,* the complexity with 

 simplicity, and with such curious co-ordination of the nervous 

 system is marvellous ; and you showed me before what 

 splendid gymnastic feats they can perform. 



* " On the locomotor system of and J. Cossar Evvart. ■ Philoso- 

 Echinoderms," by G. J. Romanes phical Transactions,' 1881, p. 829. 



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