With respect to Lepidosiren, Ganoid fishes, perhaps Ornithorhynchus, I suspect, as stated in the "Origin," (95/7. "Origin of Species" (Edition VI.), page 83.), that they have been preserved, from inhabiting fresh-water and isolated parts of the world, in which there has been less competition and less rapid progress in Natural Selection, owing to the fewness of individuals which can inhabit small areas; and where there are few individuals variation at most must be slower. There are several allusions to this notion in the "Origin," as under Amblyopsis, the blind cave-fish (95/8. "Origin," page 112.), and under Heer (95/9. "Origin," page 83.) about Madeira plants resembling the fossil and extinct plants of Europe. LETTER 96. TO JAMES LAMONT. Down, March 5th [1860?]. I am much obliged for your long and interesting letter. You have indeed good right to speak confidently about the habits of wild birds and animals; for I should think no one beside yourself has ever sported in Spitzbergen and Southern Africa. It is very curious and interesting that you should have arrived at the conclusion that so-called "Natural Selection" had been efficient in giving their peculiar colours to our grouse. I shall probably use your authority on the similar habits of our grouse and the Norwegian species. I am particularly obliged for your very curious fact of the effect produced by the introduction of the lowland grouse on the wildness of the grouse in your neighbourhood. It is a very striking instance of what crossing will do in affecting the character of a breed. Have you ever seen it stated in any sporting work that game has become wilder in this country? I wish I could get any sort of proof of the fact, for your explanation seems to me equally ingenious and probable. I have myself witnessed in South America a nearly parallel [case] with that which you mention in regard to the reindeer in Spitzbergen, with the Cervus campestris of La Plata. It feared neither man nor the sound of shot of a rifle, but was terrified at the sight of a man on horseback; every one in that country always riding. As you are so great a sportsman, perhaps you will kindly look to one very trifling point for me, as my neighbours here think it too absurd to notice--namely, whether the feet of birds are dirty, whether a few grains of dirt do not adhere occasionally to their feet. I especially want to know how this is in the case of birds like herons and waders, which stalk in the mud. You will guess that this relates to dispersal of seeds, which is one of my greatest difficulties. My health is very indifferent, and I am seldom able to attend the scientific meetings, but I sincerely hope that I may some time have the pleasure of meeting you. Pray accept my cordial thanks for your very kind letter. LETTER 97. TO G.H.K. THWAITES. Down, March 21st [1860].