My dear Sir,

I thank you very much for your suggestion, which I will carry out in the winter.¹ I find menagerie bones absolutely useless for comparison with those of the same animals of Pleistocene age.² Between wild individuals even of the same recent species there is a large amount of variation, and that variation M^r. Sanford and myself have used, or rather are using to prove the identity of Felis spelæa with F. leo, in the Palæont. Soc.³

I am | My dear Sir | Yours truly | W. Boyd Dawkins

Charles Darwin Esq. F.R.S.