My dear Sir

I am truly obliged for all the trouble which you have taken for me & for your very interesting note.—² 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.³ The rudiment sent to you was from a full-grown frog; so that if these bones are the two Cuneiforms they must, I sh^d. think, be considered to be in a rudimentary condition.— This afternoon my gardener⁴ brought me some tadpoles, with the hind-legs alone developed, & 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, & the transverse 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, & especially on the power of regrowth in amputated supernumery digits.⁵

With very sincere thanks | believe me | My dear Sir | Yours very faithfully | Ch. Darwin