My dear Sir

I learn from M^r. Busk that you are just now engaged in collecting such new facts as may bear on the origin of specific forms.¹ I cannot say that I have any facts to offer you, but some new views which have struck me while recently engaged in the study of graptolites in connexion with their hydroid affinities may interest you. They will appear in the second part of my Monograph on the Tubularian hydroids, but as it will be some time yet before the publication of this tract, I send you some proof sheets in which you will find a statement of the views to which I refer. I have marked in the margin the passages which more especially bear on the question of the descent of our existing hydroids from the ancient graptolites.²

Do not take the trouble to return the proofs but if you have any suggestions which may occur to you on this subject I should be greatly obliged by a line from you

Believe me | very sincerely yours | Geo J. Allman

Ch. Darwin Esq