254 'VARIATION UNDER DOMESTICATION.' [1867. 



count for the bright colours of the Planariae in reference to 

 sexual selection. By the way, I suppose they are herma- 

 phrodites. 



Do not forget to aid me, if in your power, with answers 

 to any of my ^questions on expression, for the subject interests 

 me greatly. With cordial thanks for your never-failing kind- 

 ness, believe me, 



Yours very sincerely, 



Charles Darwin. 



C. Darwin to C. Lyell. 



Down, July 18 [1S67]. 



My dear Lyell, — Many thanks for your long letter. I 

 am sorry to hear that you are in despair about your book ; * 

 I well know that feeling, but am now getting out of the lower 

 depths. I shall be very much pleased, if you can make the 

 least use of my present book, and do not care at all whether 

 it is published before yours. Mine will appear towards the 

 end of November of this year ; you speak of yours as not 

 coming out till November, 1868, which I hope may be an 

 error. There is nothing about Man in my book which can 

 interfere with you, so I will order all the completed clean 

 sheets to be sent (and others as soon as ready) to you, but 

 please observe you will not care for the first volume, which 

 is a mere record of the amount of variation ; but I hope the 

 second will be somewhat more interesting. Though I fear 

 the whole must be dull. 



I rejoice from my heart that you are going to speak out 

 plainly about species. My book about Man, if published, 

 will be short, and a large portion will be devoted to sexual 

 selection, to which subject I alluded in the ' Origin ' as bear- 

 ing on Man. . . . 



* The 2nd volume of the loth Edit, of the ' Principles.' 



