1864-1869] REGENERATION 2$I 



but I am now recommencing a volume in connection with Letter 177 

 the Origin. 



P.S. — If you write again I should very much like to 

 hear what your life in your new country is. 



What can be the meaning or use of the great diversity 

 of the external generative organs in your cases, in Bombus, 

 and the phytophagous coleoptera? 



What can there be in the act of copulation necessitating 

 such complex and diversified apparatus? 



To W. H. Flower. Lettcr 178 



Down, July nth, 1864. 

 I am truly obliged for all the trouble which you have 

 taken for me, and for your very interesting note. I had 

 only vaguely heard it said that frogs had a rudiment of a 

 sixth toe ; had I known that such great men had looked to the 

 point I should not have dreamed of looking myself. The rudi- 

 ment sent to you was from a full-grown frog ; so that if these 

 bones arc the two cuneiforms they must, I should think, be 

 considered to be in a rudimentary condition. This afternoon 

 my gardener brought in some tadpoles with the hind-legs 

 alone developed, and I looked at the rudiment. At this 

 age it certainly looks extremely like a digit, for the extremity 

 is enlarged like that of the adjoining real toe, and the trans- 

 verse articulation seems similar. I am sorry that the case is 

 doubtful, for if these batrachians had six toes, I certainly 

 think it would have thrown light on the truly extraordinary 

 strength of inheritance in polydactylism in so many animals, 

 and especially on the power of regeneration x in amputated 

 supernumerary digits. 



To J. D. Hooker. Letter 179 



Down [October 22nd, 1864]. 

 The Lyells have been here, and were extremely pleasant, 

 but I saw them only occasionally for ten minutes, and when 

 they went I had an awful day [of illness] ; but I am now 



1 In the first edition of Variation under Domestication the view here 

 given is upheld, but in the second edition (Vol. I., p. 459) Darwin 

 withdrew his belief that the development of supernumerary digits in 

 man is "a case of reversion to a lowly-organised progenitor provided 

 with more than five digits." See Letters 161, 270. 



