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June — 45/

Falconer showed me beautiful series of elephant & Mastodon, with structure of teeth, in every point & general structure blending in each other. — In the series the two living the American Siberian species & one Indian alternate with each other & hence not descent. Why not? is it certain the recent were created subsequently to the extinct it is probable. — How many more species unknown !!! Waterhouse says analogous series in Arvicola & Mus. gradation between fo rooted teeth & rootless →

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in one intermediate form, one has roots only when young & another only when old. (The Mastodon has tusks in lower jaw only when young; Indian Mastodon have none. As Indian elephants tusks only on one side Falconer does not believe Burchell, from habits of Indian Elephant.) The gradation in teeth of mice does not

Waterhouse insists represent true series, as judged chiefly by skulls of heads. —