P. 252, and elsewhere: I agree thoroughly with the general principle that a great area with many competing forms is necessary for much and high development; but do you not extend this principle too far--I should say much too far, considering how often several species of the same genus have been developed on very small islands? P. 265: You say that the Sittidæ extend to Madagascar, but there is no number in the tabular heading.[108] P. 359: Rhinochetus is entered in the tabular heading under No. 3 of the _Neotropical_ sub-regions.[109] Reviewers think it necessary to find some fault, and if I were to review you, the sole point which I should blame is your not giving very numerous references. These would save whoever follows you great labour. Occasionally I wished myself to know the authority for certain statements, and whether you or somebody else had originated certain subordinate views. Take the case of a man who had collected largely on some island, for instance St. Helena, and who wished to work out the geographical relations of his collection; he would, I think, feel very blank at not finding in your work precise references to all that had been written on St. Helena. I hope you will not think me a confoundedly disagreeable fellow. I may mention a capital essay which I received a few mouths ago from Axel Blytt[110] on the distribution of the plants of Scandinavia; showing the high probability of there having been secular periods alternately wet and dry; and of the important part which they have played in distribution. I wrote to Forel, who is always at work on ants, and told him of your views about the dispersal of the blind Coleoptera, and asked him to observe. I spoke to Hooker about your book, and feel sure that he would like nothing better than to consider the distribution of plants in relation to your views; but he seemed to doubt whether he should ever have time. And now I have done my jottings, and once again congratulate you on having brought out so grand a work. I have been a little disappointed at the review in _Nature_[111]--My dear Wallace, yours sincerely, CHARLES DARWIN. * * * * * _Rose Hill, Dorking. July 23, 1876._ My dear Darwin,--I should have replied sooner to your last kind and interesting letters, but they reached me in the midst of my packing previous to removal here, and I have only just now got my books and papers in a get-at-able state. And first, many thanks for your close observation in detecting the two absurd mistakes in the tabular headings.